Todas as Publicações do INCT-MI – INCT – Institutos Nacionais de Ciência e Tecnologia

304 entradas « ‹ 1 de 16 › »
1.
Carvalho, Gabriel L.; Piero, João V. B. Del; Silva, Flávia C. Assis; Amorim, Rodrigo G.; Freitas, Jair C. C.; Scopel, Wanderlã L.
Functionalized graphene sensors for detecting coffee-related compounds Journal Article
Em: Applied Surface Science, 2025, ISSN: 0169-4332.
Resumo | Links | BibTeX | Tags:
@article{Carvalho2025,
title = {Functionalized graphene sensors for detecting coffee-related compounds},
author = {Gabriel L. Carvalho and João V.B. Del Piero and Flávia C. Assis Silva and Rodrigo G. Amorim and Jair C.C. Freitas and Wanderlã L. Scopel},
doi = {10.1016/j.apsusc.2025.163739},
issn = {0169-4332},
year = {2025},
date = {2025-11-15},
urldate = {2025-06-00},
journal = {Applied Surface Science},
publisher = {Elsevier BV},
abstract = {Coffee is a globally consumed beverage that needs high quality and production standards. Consequently, concerns regarding its quality are widespread, making the identification of its chemical components and of potential substances resulting from the cultivation process highly desirable. In this work, theoretical calculations based on the density functional theory combined with non-equilibrium Green’s function were employed to assess the potential of graphene-based devices for molecular detection and sensing. The quantum calculations were used to investigate the interaction between graphene-based systems (including pristine graphene and oxygen-containing graphene sheets) and individual molecules such as caffeine, trigonelline, and glyphosate. The binding energy analysis revealed that epoxy- and hydroxyl-functionalized graphene sheets exhibit a stronger interaction with the target molecules in comparison with pristine graphene. The transmission curve obtained for each molecule allowed the identification of individual molecules on the devices based on conductance changes. Since reduced graphene oxide (rGO) is known to contain a distribution of oxygen functional groups (such as epoxy and hydroxyl groups) surrounded by large regions of interconnected hexagonal rings of sp-hybridized carbon atoms, the obtained results indicate then that different types of target molecules can be detected using an rGO-based device. This underscores the capability of carbon-based materials to exhibit remarkable sensitivity and selectivity in the detection of organic molecules, which are of special interest for molecular sensing applications in general and for the coffee production sector in particular.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Coffee is a globally consumed beverage that needs high quality and production standards. Consequently, concerns regarding its quality are widespread, making the identification of its chemical components and of potential substances resulting from the cultivation process highly desirable. In this work, theoretical calculations based on the density functional theory combined with non-equilibrium Green’s function were employed to assess the potential of graphene-based devices for molecular detection and sensing. The quantum calculations were used to investigate the interaction between graphene-based systems (including pristine graphene and oxygen-containing graphene sheets) and individual molecules such as caffeine, trigonelline, and glyphosate. The binding energy analysis revealed that epoxy- and hydroxyl-functionalized graphene sheets exhibit a stronger interaction with the target molecules in comparison with pristine graphene. The transmission curve obtained for each molecule allowed the identification of individual molecules on the devices based on conductance changes. Since reduced graphene oxide (rGO) is known to contain a distribution of oxygen functional groups (such as epoxy and hydroxyl groups) surrounded by large regions of interconnected hexagonal rings of sp-hybridized carbon atoms, the obtained results indicate then that different types of target molecules can be detected using an rGO-based device. This underscores the capability of carbon-based materials to exhibit remarkable sensitivity and selectivity in the detection of organic molecules, which are of special interest for molecular sensing applications in general and for the coffee production sector in particular.
Fechar
doi:10.1016/j.apsusc.2025.163739
Fechar
2.
Piero, João V B Del; Miwa, Roberto H.; Scopel, Wanderlã L.
Vanadium incorporation in 2D-layered MoSe2 Journal Article
Em: J. Phys.: Condens. Matter, vol. 37, não 4, 2025, ISSN: 1361-648X.
Resumo | Links | BibTeX | Tags:
@article{DelPiero2024,
title = {Vanadium incorporation in 2D-layered MoSe2},
author = {João V B Del Piero and Roberto H. Miwa and Wanderlã L. Scopel},
url = {https://iopscience.iop.org/article/10.1088/1361-648X/ad8abb/meta},
doi = {10.1088/1361-648x/ad8abb},
issn = {1361-648X},
year = {2025},
date = {2025-11-11},
urldate = {2025-01-27},
journal = {J. Phys.: Condens. Matter},
volume = {37},
number = {4},
publisher = {IOP Publishing},
abstract = {Recent advances in experimental techniques have made it possible to manipulate the structural and electronic properties of two-dimensional layered materials (2DM) through interaction with foreign atoms. Using quantum mechanics calculations based on the density functional theory, we explored the dependency of the structural, energetic, electronic, and magnetic properties of the interaction between Vanadium (V) atoms and monolayer and bilayer MoSe2. Spin-polarized metallic behavior was observed for high V concentration, and a semiconductor/metal interface emerged due to V adsorption on top of BL MoSe2. Our research demonstrated that the functionalization of 2D materials makes an important contribution to the design of spintronic devices based on a 2D-layered materials platform.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Recent advances in experimental techniques have made it possible to manipulate the structural and electronic properties of two-dimensional layered materials (2DM) through interaction with foreign atoms. Using quantum mechanics calculations based on the density functional theory, we explored the dependency of the structural, energetic, electronic, and magnetic properties of the interaction between Vanadium (V) atoms and monolayer and bilayer MoSe2. Spin-polarized metallic behavior was observed for high V concentration, and a semiconductor/metal interface emerged due to V adsorption on top of BL MoSe2. Our research demonstrated that the functionalization of 2D materials makes an important contribution to the design of spintronic devices based on a 2D-layered materials platform.
Fechar
https://iopscience.iop.org/article/10.1088/1361-648X/ad8abb/meta
doi:10.1088/1361-648x/ad8abb
Fechar
3.
Cintra, Gabriel Borelli; Pedrosa, Renan Narciso; Scopel, Wanderlã L.; Amorim, Rodrigo G.; Araujo, C. Moyses
Exploring Li intercalation in WSSe/Silicene heterostructures for Li-ion battery anodes Journal Article
Em: Surfaces and Interfaces, vol. 72, 2025, ISSN: 2468-0230.
Resumo | Links | BibTeX | Tags:
@article{Cintra2025,
title = {Exploring Li intercalation in WSSe/Silicene heterostructures for Li-ion battery anodes},
author = {Gabriel Borelli Cintra and Renan Narciso Pedrosa and Wanderlã L. Scopel and Rodrigo G. Amorim and C. Moyses Araujo},
doi = {10.1016/j.surfin.2025.106802},
issn = {2468-0230},
year = {2025},
date = {2025-09-01},
urldate = {2025-09-01},
journal = {Surfaces and Interfaces},
volume = {72},
publisher = {Elsevier BV},
abstract = {The interfacing 2D materials are promising candidates for excellent anodes focusing on energy storage Li-battery. With van der Waals gaps, these materials present genuine ion diffusion channels for lithium. In this context, we explore the incorporation of Li atoms in the WSSe/Silicene heterostructure employing ab initio calculations. It is worth mentioning that the pristine interface has a metallic behavior. Our findings reveal that intercalated lithium is more energetically favorable than it adsorbed on the surfaces of heterostructure and their counterparts. To access the lithium ionic diffusion on the material, two distinct migration barriers were examined, where the lowest had an ionic diffusion energy barrier of 0.34 eV. One interesting finding consists of an open circuit voltage (OCV) for the former case, which shows a small variation, indicating a low deviation of voltages for a small Li concentration. The results indicate a maximum volume expansion of only 0.86%, which suggests favorable structural tolerance, essential to electrode application. The interface layered 2D materials based on WSSe/Silicene demonstrated an optimistic approach as a Li-ion battery anode.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
The interfacing 2D materials are promising candidates for excellent anodes focusing on energy storage Li-battery. With van der Waals gaps, these materials present genuine ion diffusion channels for lithium. In this context, we explore the incorporation of Li atoms in the WSSe/Silicene heterostructure employing ab initio calculations. It is worth mentioning that the pristine interface has a metallic behavior. Our findings reveal that intercalated lithium is more energetically favorable than it adsorbed on the surfaces of heterostructure and their counterparts. To access the lithium ionic diffusion on the material, two distinct migration barriers were examined, where the lowest had an ionic diffusion energy barrier of 0.34 eV. One interesting finding consists of an open circuit voltage (OCV) for the former case, which shows a small variation, indicating a low deviation of voltages for a small Li concentration. The results indicate a maximum volume expansion of only 0.86%, which suggests favorable structural tolerance, essential to electrode application. The interface layered 2D materials based on WSSe/Silicene demonstrated an optimistic approach as a Li-ion battery anode.
Fechar
doi:10.1016/j.surfin.2025.106802
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4.
Han, Shulun; Li, Linyang; Tang, Chi Sin; Wang, Qi; Zhang, Lingfeng; Diao, Caozheng; Zhao, Mingwen; Sun, Shuo; Tian, Lijun; Breese, Mark B. H.; Cai, Chuanbing; Milošević, Milorad V.; Qi, Yanpeng; Wee, Andrew T. S.; Yin, Xinmao
Orbital hybridization and magnetic moment enhancement driven by charge density waves in kagome FeGe Journal Article
Em: vol. 12, não 3, 2025, ISSN: 1931-9401.
Resumo | Links | BibTeX | Tags:
@article{Han2025,
title = {Orbital hybridization and magnetic moment enhancement driven by charge density waves in kagome FeGe},
author = {Shulun Han and Linyang Li and Chi Sin Tang and Qi Wang and Lingfeng Zhang and Caozheng Diao and Mingwen Zhao and Shuo Sun and Lijun Tian and Mark B. H. Breese and Chuanbing Cai and Milorad V. Milošević and Yanpeng Qi and Andrew T. S. Wee and Xinmao Yin},
doi = {10.1063/5.0260257},
issn = {1931-9401},
year = {2025},
date = {2025-07-01},
urldate = {2025-09-01},
volume = {12},
number = {3},
publisher = {AIP Publishing},
abstract = {Interactions among various electronic states, such as charge density waves (CDWs), magnetism, and superconductivity, are pivotal in strongly correlated systems. While the relationship between CDWs and superconductivity has been extensively studied, the interplay between CDWs and magnetic order remains largely elusive. Kagome lattices, with their intrinsic nontrivial topology, charge order, and magnetism, provide a compelling framework for investigating these interactions. In this work, we unravel the orbital origins of magnetic moment modulation induced by CDW in the kagome magnet FeGe, a system exhibiting a unique coupling between CDW and magnetism. The combination of x-ray absorption spectroscopic experiments and first-principles calculations shed light on the temperature-dependent behavior of Fe3d–Ge4p orbital hybridization and corroborate its significant impact on the magnetic properties of FeGe. These findings introduce an orbital dimension to the correlation between charge and magnetic degrees of freedom, advancing our understanding of the intriguing quantum phases resulting from this interplay.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Interactions among various electronic states, such as charge density waves (CDWs), magnetism, and superconductivity, are pivotal in strongly correlated systems. While the relationship between CDWs and superconductivity has been extensively studied, the interplay between CDWs and magnetic order remains largely elusive. Kagome lattices, with their intrinsic nontrivial topology, charge order, and magnetism, provide a compelling framework for investigating these interactions. In this work, we unravel the orbital origins of magnetic moment modulation induced by CDW in the kagome magnet FeGe, a system exhibiting a unique coupling between CDW and magnetism. The combination of x-ray absorption spectroscopic experiments and first-principles calculations shed light on the temperature-dependent behavior of Fe3d–Ge4p orbital hybridization and corroborate its significant impact on the magnetic properties of FeGe. These findings introduce an orbital dimension to the correlation between charge and magnetic degrees of freedom, advancing our understanding of the intriguing quantum phases resulting from this interplay.
Fechar
doi:10.1063/5.0260257
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5.
Buzelli, Thiago; Ipaves, Bruno; Gollino, Felipe; Almeida, Wanda Pereira; Galvão, Douglas Soares; da Silva Autreto, Pedro Alves
Machine learning-based analysis of electronic properties as predictors of anticholinesterase activity in chalcone derivatives Journal Article
Em: Computational and Theoretical Chemistry, vol. 1249, 2025, ISSN: 2210-271X.
Resumo | Links | BibTeX | Tags:
@article{Buzelli2025,
title = {Machine learning-based analysis of electronic properties as predictors of anticholinesterase activity in chalcone derivatives},
author = {Thiago Buzelli and Bruno Ipaves and Felipe Gollino and Wanda Pereira Almeida and Douglas Soares Galvão and Pedro Alves da Silva Autreto},
doi = {10.1016/j.comptc.2025.115268},
issn = {2210-271X},
year = {2025},
date = {2025-07-00},
urldate = {2025-07-00},
journal = {Computational and Theoretical Chemistry},
volume = {1249},
publisher = {Elsevier BV},
abstract = {In this study, we investigated the correlation between the electronic properties of anticholinesterase compounds and their biological activity. While this correlation has been effectively explored in previous studies, we employed a more advanced approach: machine learning. We analyzed a set of 22 molecules sharing a similar chalcone skeleton, categorizing them into two groups based on their IC50 indices: high and low activity. Using the open-source software Orca, we calculated the geometries and electronic structures of these molecules. Over a hundred parameters were extracted, including Mulliken and Lowdin electronic populations, molecular orbital energies, and Mayer’s free valences, forming the foundation for machine learning features. Through our analysis, we developed models capable of distinguishing between the two groups. Notably, the most informative descriptor relied solely on electronic populations and orbital energies. Identifying computationally relevant properties for biological activity enhances drug development efficiency, saving time and resources. },
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
In this study, we investigated the correlation between the electronic properties of anticholinesterase compounds and their biological activity. While this correlation has been effectively explored in previous studies, we employed a more advanced approach: machine learning. We analyzed a set of 22 molecules sharing a similar chalcone skeleton, categorizing them into two groups based on their IC50 indices: high and low activity. Using the open-source software Orca, we calculated the geometries and electronic structures of these molecules. Over a hundred parameters were extracted, including Mulliken and Lowdin electronic populations, molecular orbital energies, and Mayer’s free valences, forming the foundation for machine learning features. Through our analysis, we developed models capable of distinguishing between the two groups. Notably, the most informative descriptor relied solely on electronic populations and orbital energies. Identifying computationally relevant properties for biological activity enhances drug development efficiency, saving time and resources.
Fechar
doi:10.1016/j.comptc.2025.115268
Fechar
6.
Kaewmaraya, T.; Amorim, Rodrigo G.; Thatsami, N.; Moontragoon, P.; Pinitsoontorn, S.; Bae, H.; Lee, H.; Nasiri, N.; Hussain, T.
Highly efficient room-temperature ethylene sensing with molybdenum based transition metal dichalcogenides Journal Article
Em: Applied Surface Science, vol. 697, 2025, ISSN: 0169-4332.
Links | BibTeX | Tags:
@article{Kaewmaraya2025,
title = {Highly efficient room-temperature ethylene sensing with molybdenum based transition metal dichalcogenides},
author = {T. Kaewmaraya and Rodrigo G. Amorim and N. Thatsami and P. Moontragoon and S. Pinitsoontorn and H. Bae and H. Lee and N. Nasiri and T. Hussain},
doi = {10.1016/j.apsusc.2025.162984},
issn = {0169-4332},
year = {2025},
date = {2025-07-00},
urldate = {2025-07-00},
journal = {Applied Surface Science},
volume = {697},
publisher = {Elsevier BV},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
doi:10.1016/j.apsusc.2025.162984
Fechar
7.
Mannino, Anthony; Arvelos, Graciele M.; Kaushik, Kedarsh; Artacho, Emilio; Ordejon, Pablo; Rocha, Alexandre R.; Pedroza, Luana S.; Fernández-Serra, Marivi
First-Principles Nanocapacitor Simulations of the Optical Dielectric Constant in Water Ice Miscellaneous
2025.
Resumo | Links | BibTeX | Tags:
@misc{mannino2025firstprinciplesnanocapacitorsimulationsoptical,
title = {First-Principles Nanocapacitor Simulations of the Optical Dielectric Constant in Water Ice},
author = {Anthony Mannino and Graciele M. Arvelos and Kedarsh Kaushik and Emilio Artacho and Pablo Ordejon and Alexandre R. Rocha and Luana S. Pedroza and Marivi Fernández-Serra},
url = {https://arxiv.org/abs/2506.23003},
year = {2025},
date = {2025-06-28},
urldate = {2025-01-01},
abstract = {We introduce a combined density functional theory (DFT) and non-equilibrium Green's function (NEGF) framework to compute the capacitance of nanocapacitors and directly extract the dielectric response of a sub-nanometer dielectric under bias. We identify that at the nanoscale conventional capacitance evaluations based on stored charge per unit voltage suffer from an ill-posed partitioning of electrode and dielectric charge. This partitioning directly impacts the geometric definition of capacitance through the capacitor width, which in turn makes the evaluation of dielectric response uncertain. This ambiguous separation further induces spurious interfacial polarizability when analyzed via maximally localized Wannier functions. Focusing on crystalline ice, we develop a robust charge-separation protocol that yields unique capacitance-derived polarizability and dielectric constants, unequivocally demonstrating that confinement neither alters ice's intrinsic electronic response nor its insensitivity to proton order. Our results lay the groundwork for rigorous interpretation of capacitor measurements in low-dimensional dielectric materials.},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}

Fechar
We introduce a combined density functional theory (DFT) and non-equilibrium Green's function (NEGF) framework to compute the capacitance of nanocapacitors and directly extract the dielectric response of a sub-nanometer dielectric under bias. We identify that at the nanoscale conventional capacitance evaluations based on stored charge per unit voltage suffer from an ill-posed partitioning of electrode and dielectric charge. This partitioning directly impacts the geometric definition of capacitance through the capacitor width, which in turn makes the evaluation of dielectric response uncertain. This ambiguous separation further induces spurious interfacial polarizability when analyzed via maximally localized Wannier functions. Focusing on crystalline ice, we develop a robust charge-separation protocol that yields unique capacitance-derived polarizability and dielectric constants, unequivocally demonstrating that confinement neither alters ice's intrinsic electronic response nor its insensitivity to proton order. Our results lay the groundwork for rigorous interpretation of capacitor measurements in low-dimensional dielectric materials.
Fechar
https://arxiv.org/abs/2506.23003
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8.
Lizárraga, K.; Guerra, J. A.; Enrique-Moran, L. A.; Serquen, E.; Ventura, E.; Villegas, Cesar E. P.; Rocha, A. R.; Venezuela, P.
Determining Exciton Binding Energy and Reduced Effective Mass in Metal Tri-Halide Perovskites from Optical and Impedance Spectroscopy Measurements Miscellaneous
2025.
Resumo | Links | BibTeX | Tags:
@misc{lizárraga2025determiningexcitonbindingenergy,
title = {Determining Exciton Binding Energy and Reduced Effective Mass in Metal Tri-Halide Perovskites from Optical and Impedance Spectroscopy Measurements},
author = {K. Lizárraga and J. A. Guerra and L. A. Enrique-Moran and E. Serquen and E. Ventura and Cesar E. P. Villegas and A. R. Rocha and P. Venezuela},
url = {https://arxiv.org/abs/2506.22680},
year = {2025},
date = {2025-06-27},
urldate = {2025-06-27},
abstract = {Accurate determination of the exciton binding energy and reduced effective mass in halide perovskites is of utmost importance for the selective design of optoelectronic devices. Although these properties are currently determined by several spectroscopic techniques, complementary theoretical models are often required to bridge macroscopic and microscopic properties. Here, we present a novel method to determine these quantities while fully accounting for polarization effects due to carrier interactions with longitudinal optical phonons. Our approach estimates the exciton-polaron binding energy from optical absorption measurements using a recently developed Elliott based Band Fluctuations model. The reduced effective mass is obtained via the Pollmann-Buttner exciton-polaron model, which is based on the Frohlich polaron framework, where the strength of the electron-phonon interaction arises from changes in the dielectric properties. The procedure is applied to the family of perovskites ABX3 (A = MA, FA, Cs; B = Pb; X = I, Br, Cl), showing excellent agreement with high field magnetoabsorption and other optical-resolved techniques. The results suggest that the Pollmann-Buttner model offers a robust and novel approach for determining the reduced effective mass in metal tri-halide perovskites and other polar materials exhibiting free exciton bands.
},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}

Fechar
Accurate determination of the exciton binding energy and reduced effective mass in halide perovskites is of utmost importance for the selective design of optoelectronic devices. Although these properties are currently determined by several spectroscopic techniques, complementary theoretical models are often required to bridge macroscopic and microscopic properties. Here, we present a novel method to determine these quantities while fully accounting for polarization effects due to carrier interactions with longitudinal optical phonons. Our approach estimates the exciton-polaron binding energy from optical absorption measurements using a recently developed Elliott based Band Fluctuations model. The reduced effective mass is obtained via the Pollmann-Buttner exciton-polaron model, which is based on the Frohlich polaron framework, where the strength of the electron-phonon interaction arises from changes in the dielectric properties. The procedure is applied to the family of perovskites ABX3 (A = MA, FA, Cs; B = Pb; X = I, Br, Cl), showing excellent agreement with high field magnetoabsorption and other optical-resolved techniques. The results suggest that the Pollmann-Buttner model offers a robust and novel approach for determining the reduced effective mass in metal tri-halide perovskites and other polar materials exhibiting free exciton bands.

Fechar
https://arxiv.org/abs/2506.22680
Fechar
9.
Vidarte, Kevin J. U.; Lewenkopf, Caio; Lima, F. Crasto; Miwa, R. Hiroki; Riffo, Felipe Pérez; Morell, Eric Suárez
Unveiling the Electronic Origin of Anomalous Contact Conductance in Twisted Bilayer Graphene Miscellaneous
2025.
Resumo | Links | BibTeX | Tags:
@misc{vidarte2025unveilingelectronicoriginanomalous,
title = {Unveiling the Electronic Origin of Anomalous Contact Conductance in Twisted Bilayer Graphene},
author = {Kevin J. U. Vidarte and Caio Lewenkopf and F. Crasto Lima and R. Hiroki Miwa and Felipe Pérez Riffo and Eric Suárez Morell},
url = {https://arxiv.org/abs/2506.21721},
year = {2025},
date = {2025-06-26},
urldate = {2025-01-01},
abstract = {This study theoretically investigates the contact conductance in twisted bilayer graphene (TBG), providing a theoretical explanation for recent experimental observations from scanning tunneling microscopy (STM) and conductive atomic force microscopy (c-AFM). These experiments revealed a surprising non-monotonic current pattern as a function of the TBG rotation angle θ, with a peak at θ ≈ 5 ◦, a finding that markedly departs from the well-known magic angle TBG behavior. To elucidate this phenomenon, we develop a comprehensive theoretical and computational framework. Our calculations, performed on both relaxed and rigid TBG structures, simulate contact conductance by analyzing the local density of states across a range of biases and rotational angles. Contrary to the current interpretation, our results demonstrate that the maximum conductance at θ ≈ 5 o is not caused by structural relaxation or AA stacking zone changes. Instead, we attribute this peak
to the evolution of the electronic band structure, specifically the shifting of van Hove singularities (vHs) to the Fermi level as the twist angle decreases. We further show that the precise location of this conductance maximum is dependent on the applied bias voltage. This interplay between twist angle, bias, and vHs energy provides a robust explanation for the experimental findings.},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}

Fechar
This study theoretically investigates the contact conductance in twisted bilayer graphene (TBG), providing a theoretical explanation for recent experimental observations from scanning tunneling microscopy (STM) and conductive atomic force microscopy (c-AFM). These experiments revealed a surprising non-monotonic current pattern as a function of the TBG rotation angle θ, with a peak at θ ≈ 5 ◦, a finding that markedly departs from the well-known magic angle TBG behavior. To elucidate this phenomenon, we develop a comprehensive theoretical and computational framework. Our calculations, performed on both relaxed and rigid TBG structures, simulate contact conductance by analyzing the local density of states across a range of biases and rotational angles. Contrary to the current interpretation, our results demonstrate that the maximum conductance at θ ≈ 5 o is not caused by structural relaxation or AA stacking zone changes. Instead, we attribute this peak
to the evolution of the electronic band structure, specifically the shifting of van Hove singularities (vHs) to the Fermi level as the twist angle decreases. We further show that the precise location of this conductance maximum is dependent on the applied bias voltage. This interplay between twist angle, bias, and vHs energy provides a robust explanation for the experimental findings.
Fechar
https://arxiv.org/abs/2506.21721
Fechar
10.
Oliveira, Douglas Soares; Kuritza, Danilo P.; Zavarize, Mariana; Padilha, Jose E.; Cotta, Mônica Alonso
Atomistic Modeling of Gap Nanowire Growth and Heat Transport via Interatomic Potential: Implications for Thermoelectric Applications Journal Article
Em: ACS Appl. Nano Mater., 2025, ISSN: 2574-0970.
Resumo | Links | BibTeX | Tags:
@article{Oliveira2025,
title = {Atomistic Modeling of Gap Nanowire Growth and Heat Transport via Interatomic Potential: Implications for Thermoelectric Applications},
author = {Douglas Soares Oliveira and Danilo P. Kuritza and Mariana Zavarize and Jose E. Padilha and Mônica Alonso Cotta},
doi = {10.1021/acsanm.5c01892},
issn = {2574-0970},
year = {2025},
date = {2025-06-24},
urldate = {2025-06-24},
journal = {ACS Appl. Nano Mater.},
publisher = {American Chemical Society (ACS)},
abstract = {Atomistic simulations of gallium phosphide (GaP) nanomaterials are limited by the absence of reliable and publicly available interatomic potentials. In this work, we develop and parametrize a classical angular-dependent potential for GaP based on force-matching against density functional theory reference data, enabling accurate large-scale simulations of GaP-based nanoscale systems. The developed potential effectively reproduces essential structural, elastic, and energetic properties of bulk GaP in both zinc-blende and wurtzite phases, despite some deviations from experimental reference values. Through molecular dynamics simulations, we demonstrate the potential’s ability to describe key aspects of self-catalyzed vapor–liquid–solid growth in GaP nanowires, such as nucleation dynamics, temperature stability limits, and the influence of catalyst geometry. Furthermore, thermal transport simulations reveal that the model accurately captures qualitative trends regarding the impact of nanostructure size and surface morphology on thermal conductivity. Additionally, we investigate thermal rectification effects in telescopic GaP nanowires, observing measurable heat-flow asymmetries. These findings provide insights into phonon engineering strategies at the nanoscale, highlighting the relevance of GaP nanostructures for next-generation thermoelectric applications. The interatomic potential presented here will be made publicly available, offering a valuable computational tool for future investigations of GaP nanomaterials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Atomistic simulations of gallium phosphide (GaP) nanomaterials are limited by the absence of reliable and publicly available interatomic potentials. In this work, we develop and parametrize a classical angular-dependent potential for GaP based on force-matching against density functional theory reference data, enabling accurate large-scale simulations of GaP-based nanoscale systems. The developed potential effectively reproduces essential structural, elastic, and energetic properties of bulk GaP in both zinc-blende and wurtzite phases, despite some deviations from experimental reference values. Through molecular dynamics simulations, we demonstrate the potential’s ability to describe key aspects of self-catalyzed vapor–liquid–solid growth in GaP nanowires, such as nucleation dynamics, temperature stability limits, and the influence of catalyst geometry. Furthermore, thermal transport simulations reveal that the model accurately captures qualitative trends regarding the impact of nanostructure size and surface morphology on thermal conductivity. Additionally, we investigate thermal rectification effects in telescopic GaP nanowires, observing measurable heat-flow asymmetries. These findings provide insights into phonon engineering strategies at the nanoscale, highlighting the relevance of GaP nanostructures for next-generation thermoelectric applications. The interatomic potential presented here will be made publicly available, offering a valuable computational tool for future investigations of GaP nanomaterials.
Fechar
doi:10.1021/acsanm.5c01892
Fechar
11.
Marinho, Enesio; Dias, Alexandre C.; Gomes, Lidia C.; Seridonio, Antonio C. F.; Meira, Gabriel M. C.; de Souza, Mariano; Soares, Samuel M.; Squillante, Lucas; Venezuela, Pedro; Rocha, Alexandre R.; Villegas, Cesar E. P.
Optoelectronic properties of boron monochalcogenide monolayers: Quasiparticle and excitonic effects from first principles Journal Article
Em: Phys. Rev. B, vol. 111, não 23, 2025, ISSN: 2469-9969.
Resumo | Links | BibTeX | Tags:
@article{Marinho2025,
title = {Optoelectronic properties of boron monochalcogenide monolayers: Quasiparticle and excitonic effects from first principles},
author = {Enesio Marinho and Alexandre C. Dias and Lidia C. Gomes and Antonio C. F. Seridonio and Gabriel M. C. Meira and Mariano de Souza and Samuel M. Soares and Lucas Squillante and Pedro Venezuela and Alexandre R. Rocha and Cesar E. P. Villegas},
doi = {10.1103/v37y-njhk},
issn = {2469-9969},
year = {2025},
date = {2025-06-23},
urldate = {2025-06-00},
journal = {Phys. Rev. B},
volume = {111},
number = {23},
publisher = {American Physical Society (APS)},
abstract = {We investigate the linear optical response and excitonic landscape in boron monochalcogenide (B⁢𝑋, 𝑋 = S, Se, Te) single layers using ab initio many-body perturbation theory. These 2D monochalcogenides are wide band gap semiconductors, with the valence band exhibiting a quasiflat caldera-shaped dispersion in BS and BSe sheets, associated with strong van Hove singularities at the Fermi level in the density of states, an electronic feature that plays a crucial role in the emergence of strong excitonic effects. By solving the Bethe-Salpeter equation on top of 𝐺0⁡𝑊0 quasiparticle energies, our results reveal that bound excitons arise from direct optical transitions between the highest occupied band and the lowest unoccupied band along the Γ−𝑀 and Γ−𝐾 paths. Additionally, in BS and BSe monolayers, we identify excitons that are bright for in-plane polarized incident light while becoming dark for out-of-plane polarization, and other excitons with the opposite behavior. The optical selection rules are described using group-theory analysis of wave-function symmetries, determining whether optical transitions are dipole allowed or forbidden. Furthermore, exciton radiative lifetimes are estimated to range from 0.2 ns to 1.6 ns at room temperature, while exciton binding energies are significantly high, ranging from 0.6 eV to 1.2 eV for both indirect ground-state excitons and zero-momentum direct excitons. Finally, the strong electron-hole interactions in these materials lead to the formation of tightly bound excitons with a small radius, paving the way for excitonic Bose-Einstein condensation in B⁢𝑋 monolayers. Our study sheds light on the complex excitonic features of single-layer B⁢𝑋, emphasizing its potential for cutting-edge applications in exciton-driven optoelectronics and quantum technologies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
We investigate the linear optical response and excitonic landscape in boron monochalcogenide (B⁢𝑋, 𝑋 = S, Se, Te) single layers using ab initio many-body perturbation theory. These 2D monochalcogenides are wide band gap semiconductors, with the valence band exhibiting a quasiflat caldera-shaped dispersion in BS and BSe sheets, associated with strong van Hove singularities at the Fermi level in the density of states, an electronic feature that plays a crucial role in the emergence of strong excitonic effects. By solving the Bethe-Salpeter equation on top of 𝐺0⁡𝑊0 quasiparticle energies, our results reveal that bound excitons arise from direct optical transitions between the highest occupied band and the lowest unoccupied band along the Γ−𝑀 and Γ−𝐾 paths. Additionally, in BS and BSe monolayers, we identify excitons that are bright for in-plane polarized incident light while becoming dark for out-of-plane polarization, and other excitons with the opposite behavior. The optical selection rules are described using group-theory analysis of wave-function symmetries, determining whether optical transitions are dipole allowed or forbidden. Furthermore, exciton radiative lifetimes are estimated to range from 0.2 ns to 1.6 ns at room temperature, while exciton binding energies are significantly high, ranging from 0.6 eV to 1.2 eV for both indirect ground-state excitons and zero-momentum direct excitons. Finally, the strong electron-hole interactions in these materials lead to the formation of tightly bound excitons with a small radius, paving the way for excitonic Bose-Einstein condensation in B⁢𝑋 monolayers. Our study sheds light on the complex excitonic features of single-layer B⁢𝑋, emphasizing its potential for cutting-edge applications in exciton-driven optoelectronics and quantum technologies.
Fechar
doi:10.1103/v37y-njhk
Fechar
12.
da C. Dias, Victor M. S.; Kuritza, Danilo P.; de Oliveira, Igor S. S.; Padilha, José E.; Miwa, R. H.
Catenary-like Rippled Biphenylene/Graphene Lateral Heterojunction Journal Article
Em: J. Phys. Chem. C, 2025, ISSN: 1932-7455.
Resumo | Links | BibTeX | Tags:
@article{daC.Dias2025,
title = {Catenary-like Rippled Biphenylene/Graphene Lateral Heterojunction},
author = {Victor M. S. da C. Dias and Danilo P. Kuritza and Igor S. S. de Oliveira and José E. Padilha and R. H. Miwa},
doi = {10.1021/acs.jpcc.5c01823},
issn = {1932-7455},
year = {2025},
date = {2025-06-18},
urldate = {2025-06-18},
journal = {J. Phys. Chem. C},
publisher = {American Chemical Society (ACS)},
abstract = {In this study, we conduct a first-principles analysis to explore the structural and electronic properties of curved biphenylene/graphene lateral junctions (BPN/G). We started our investigation focusing on the energetic stability of BPN/G by varying the width of the graphene region, BPN/G. The electronic structure of BPN/G reveals (i) the formation of metallic channels mostly localized along the BPN stripes, where (ii) the features of the energy bands near the Fermi level are ruled by the width (n) of the graphene regions, G. In the sequence, we find that the hydrogenation of BPN/G results in a semiconductor system with a catenary-like rippled geometry. The electronic states of the hydrogenated system are mainly confined in the curved G regions, and the dependence of the bandgap on the width of G is similar to that of hydrogenated armchair graphene nanoribbons. The effects of curvature on the electronic structure, analyzed in terms of external mechanical strain, revealed that the increase or decrease of the band gap is also dictated by the width of the G region. Further electronic transport calculations reveal a combination of strong transmission anisotropy and the emergence of negative differential resistance. Based on these findings, we believe that rippled biphenylene/graphene systems can be useful for the design of two-dimensional nanodevices.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
In this study, we conduct a first-principles analysis to explore the structural and electronic properties of curved biphenylene/graphene lateral junctions (BPN/G). We started our investigation focusing on the energetic stability of BPN/G by varying the width of the graphene region, BPN/G. The electronic structure of BPN/G reveals (i) the formation of metallic channels mostly localized along the BPN stripes, where (ii) the features of the energy bands near the Fermi level are ruled by the width (n) of the graphene regions, G. In the sequence, we find that the hydrogenation of BPN/G results in a semiconductor system with a catenary-like rippled geometry. The electronic states of the hydrogenated system are mainly confined in the curved G regions, and the dependence of the bandgap on the width of G is similar to that of hydrogenated armchair graphene nanoribbons. The effects of curvature on the electronic structure, analyzed in terms of external mechanical strain, revealed that the increase or decrease of the band gap is also dictated by the width of the G region. Further electronic transport calculations reveal a combination of strong transmission anisotropy and the emergence of negative differential resistance. Based on these findings, we believe that rippled biphenylene/graphene systems can be useful for the design of two-dimensional nanodevices.
Fechar
doi:10.1021/acs.jpcc.5c01823
Fechar
13.
Lara, T. F. O.; Barros, E. B.; Lima, W. P.; Nascimento, J. P. G.; Jr., J. Milton Pereira; Pereira, T. A. S.; Costa, D. R.
Electronic properties of multilayered Lieb, transition, and Kagome lattices Miscellaneous
2025.
Resumo | Links | BibTeX | Tags:
@misc{lara2025electronicpropertiesmultilayeredlieb,
title = {Electronic properties of multilayered Lieb, transition, and Kagome lattices},
author = {T. F. O. Lara and E. B. Barros and W. P. Lima and J. P. G. Nascimento and J. Milton Pereira Jr. and T. A. S. Pereira and D. R. Costa},
url = {https://arxiv.org/abs/2506.15023},
year = {2025},
date = {2025-06-17},
urldate = {2025-01-01},
abstract = {Based on the interconvertibility feature shared between monolayer Lieb and Kagome lattices, which allows mapping transition lattice's stages between these two limits (), in this work we extend the recently proposed one-control () parameter tight-binding model for the case of a multilayer Lieb-Kagome system, by considering the two most-common stacks: AA and AB (Bernal). We systematically study the band transformations between the two lattices by adjusting the interlayer hopping and distance, with or without considering the influence of the nearest interlayer neighbors, for different numbers of stacked layers, and under the application of an external perpendicular electric field. The energetic changes are understood from the perspective of the layer dependence of the pseudospin components and the total probability density distributions. The present framework provides an appropriate and straightforward theoretical approach to continuously investigate the evolution of electronic properties in the multilayer Lieb-Kagome system under various external effects.},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}

Fechar
Based on the interconvertibility feature shared between monolayer Lieb and Kagome lattices, which allows mapping transition lattice's stages between these two limits (), in this work we extend the recently proposed one-control () parameter tight-binding model for the case of a multilayer Lieb-Kagome system, by considering the two most-common stacks: AA and AB (Bernal). We systematically study the band transformations between the two lattices by adjusting the interlayer hopping and distance, with or without considering the influence of the nearest interlayer neighbors, for different numbers of stacked layers, and under the application of an external perpendicular electric field. The energetic changes are understood from the perspective of the layer dependence of the pseudospin components and the total probability density distributions. The present framework provides an appropriate and straightforward theoretical approach to continuously investigate the evolution of electronic properties in the multilayer Lieb-Kagome system under various external effects.
Fechar
https://arxiv.org/abs/2506.15023
Fechar
14.
Oliveira, P. R. A; Coelho, I.; Felix, G.; Venezuela, P.; Stavale, F.
In situ growth of a type-II ZnO/ZnS heterostructure:From stability to band-offset Miscellaneous
2025.
Resumo | Links | BibTeX | Tags:
@misc{deoliveira2025situgrowthtypeiiznozns,
title = {In situ growth of a type-II ZnO/ZnS heterostructure:From stability to band-offset},
author = {P. R. A Oliveira and I. Coelho and G. Felix and P. Venezuela and F. Stavale},
url = {https://arxiv.org/abs/2506.14499},
year = {2025},
date = {2025-06-17},
urldate = {2025-01-01},
abstract = {We have successfully obtained a ZnO/ZnS heterostructure by heating a ZnS(001) single crystal in a controlled impurities-free oxygen atmosphere.
Combining X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM), we explore the stability, electronic structure, and morphology of that interface. Our XPS measurements reveal a binding energy shift of the core-level peaks, indicating a band-bending effect due to the formation of a hybrid ZnO/ZnS interface. In addition, AFM measurements show that exposure of ZnS single-crystal to an oxygen atmosphere leads to the formation of ZnO/ZnS-like islands. Interestingly, our band-offset estimation suggest a type-II heterostructure arrangement with suitable electronic edges positions that turn ZnO/ZnS heterostructure a promising platform for catalytic applications, particularly hydrogen and oxygen evolution reactions.
},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}

Fechar
We have successfully obtained a ZnO/ZnS heterostructure by heating a ZnS(001) single crystal in a controlled impurities-free oxygen atmosphere.
Combining X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM), we explore the stability, electronic structure, and morphology of that interface. Our XPS measurements reveal a binding energy shift of the core-level peaks, indicating a band-bending effect due to the formation of a hybrid ZnO/ZnS interface. In addition, AFM measurements show that exposure of ZnS single-crystal to an oxygen atmosphere leads to the formation of ZnO/ZnS-like islands. Interestingly, our band-offset estimation suggest a type-II heterostructure arrangement with suitable electronic edges positions that turn ZnO/ZnS heterostructure a promising platform for catalytic applications, particularly hydrogen and oxygen evolution reactions.

Fechar
https://arxiv.org/abs/2506.14499
Fechar
15.
L. Squillante, Soares
Uma introdução compreensiva sobre fenômenos eletrônicos fortemente correlacionados Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{nokey,
title = {Uma introdução compreensiva sobre fenômenos eletrônicos fortemente correlacionados},
author = {Squillante, L., Soares, S., Marinho Jr., E., Alexandre Reily Rocha, Figueira, M., Seridonio, A., & de Souza, M.},
url = {https://preprints.scielo.org/index.php/scielo/preprint/view/12120},
doi = {https://doi.org/10.1590/SciELOPreprints.12120},
year = {2025},
date = {2025-06-03},
urldate = {2025-06-03},
abstract = {O modelo do gás de elétrons proposto por Fermi em 1926 constitui uma das primeiras aplicações diretas da Mecânica Quântica na descrição das propriedades físicas de sólidos. Em particular, a descrição matemática da contribuição eletrônica para o calor específico consiste em um hallmark neste campo. No entanto, manifestações exóticas da matéria não podem ser descritas pelo modelo do gás de Fermi e pela teoria de bandas. Exemplos incluem a fase isolante de Mott e o alto valor do coeficiente de Sommerfeld para os chamados férmions pesados. Nesta contribuição, revisitamos de forma compreensiva os conceitos fundamentais relacionados aos fenômenos eletrônicos fortemente correlacionados. Focamos em uma análise do modelo de Hubbard para o dímero de Mott em conexão direta com tópicos atuais de pesquisa e observações experimentais. Revisitamos também brevemente os modelos de Fermi-Hubbard, Bose-Fermi-Hubbard, Anderson de uma única impureza,
Su–Schrieffer–Heeger,},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
O modelo do gás de elétrons proposto por Fermi em 1926 constitui uma das primeiras aplicações diretas da Mecânica Quântica na descrição das propriedades físicas de sólidos. Em particular, a descrição matemática da contribuição eletrônica para o calor específico consiste em um hallmark neste campo. No entanto, manifestações exóticas da matéria não podem ser descritas pelo modelo do gás de Fermi e pela teoria de bandas. Exemplos incluem a fase isolante de Mott e o alto valor do coeficiente de Sommerfeld para os chamados férmions pesados. Nesta contribuição, revisitamos de forma compreensiva os conceitos fundamentais relacionados aos fenômenos eletrônicos fortemente correlacionados. Focamos em uma análise do modelo de Hubbard para o dímero de Mott em conexão direta com tópicos atuais de pesquisa e observações experimentais. Revisitamos também brevemente os modelos de Fermi-Hubbard, Bose-Fermi-Hubbard, Anderson de uma única impureza,
Su–Schrieffer–Heeger,
Fechar
https://preprints.scielo.org/index.php/scielo/preprint/view/12120
doi:https://doi.org/10.1590/SciELOPreprints.12120
Fechar
16.
Sousa, Frederico B.; Fujisawa, Kazunori; Menescal, Felipe; Matos, Matheus J. S.; Pimenta, Marcos A.; Chacham, Helio; Terrones, Mauricio; Malard, Leandro M.; Carvalho, Bruno R.
Optical spectroscopy of defects in atomically thin transition metal dichalcogenides Journal Article
Em: vol. 12, não 2, 2025, ISSN: 1931-9401.
Resumo | Links | BibTeX | Tags:
@article{Sousa2025b,
title = {Optical spectroscopy of defects in atomically thin transition metal dichalcogenides},
author = {Frederico B. Sousa and Kazunori Fujisawa and Felipe Menescal and Matheus J. S. Matos and Marcos A. Pimenta and Helio Chacham and Mauricio Terrones and Leandro M. Malard and Bruno R. Carvalho},
doi = {10.1063/5.0251288},
issn = {1931-9401},
year = {2025},
date = {2025-05-28},
urldate = {2025-06-01},
volume = {12},
number = {2},
publisher = {AIP Publishing},
abstract = {In this review, we address the optical signatures of defects in two-dimensional transition metal dichalcogenides (2D TMDs), whether they occur unintentionally during growth or are deliberately introduced post-growth. We detail their primary responses as probed by photoluminescence (PL), magneto-PL, Raman, tip-enhanced PL and Raman, and nonlinear spectroscopies. Defects significantly impact the electronic, vibrational, magneto-optical, and nonlinear properties of TMDs, influencing outcomes based on application needs. This comprehensive overview highlights the distinctive optical fingerprints of various defects, providing guidance for their identification and characterization. Additionally, we discuss new optical phenomena induced by defects in TMD monolayers and future challenges in defect engineering for these materials. The insights from this review underscore the potential of TMDs for technological applications, with advancements in spectroscopy and defect engineering driving future innovations and enhancing our understanding of these materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
In this review, we address the optical signatures of defects in two-dimensional transition metal dichalcogenides (2D TMDs), whether they occur unintentionally during growth or are deliberately introduced post-growth. We detail their primary responses as probed by photoluminescence (PL), magneto-PL, Raman, tip-enhanced PL and Raman, and nonlinear spectroscopies. Defects significantly impact the electronic, vibrational, magneto-optical, and nonlinear properties of TMDs, influencing outcomes based on application needs. This comprehensive overview highlights the distinctive optical fingerprints of various defects, providing guidance for their identification and characterization. Additionally, we discuss new optical phenomena induced by defects in TMD monolayers and future challenges in defect engineering for these materials. The insights from this review underscore the potential of TMDs for technological applications, with advancements in spectroscopy and defect engineering driving future innovations and enhancing our understanding of these materials.
Fechar
doi:10.1063/5.0251288
Fechar
17.
Oliveira, Caique C.; Autreto, Pedro A. S.
Strain Modulated Catalytic Activity of Pt2XSe3 (X = Hg, Zn) for Hydrogen Evolution Reaction Miscellaneous
2025.
Resumo | Links | BibTeX | Tags:
@misc{oliveira2025strainmodulatedcatalyticactivity,
title = {Strain Modulated Catalytic Activity of Pt2XSe3 (X = Hg, Zn) for Hydrogen Evolution Reaction},
author = {Caique C. Oliveira and Pedro A. S. Autreto},
url = {https://arxiv.org/abs/2505.18338},
year = {2025},
date = {2025-05-23},
urldate = {2025-01-01},
abstract = {The catalytic properties of P t2XSe3 (X = Hg, Zn) in hydrogen-electrode- (HER-) based catalysts have been investigated based on state-of-the-art ab initio simulations. Our results show that the late transition metal sites (Hg and Zn) exhibit the best activity for HER in an acidic environment. Furthermore, lattice stretching and compression can effectively modulate the H binding energy, achieving almost thermoneutral adsorption at 3% compressive strain. The changes are attributed to the modulation in the d-band centers of late transition metal sites, as well as the depletion of charge population on bonding states, contributing to the destabilization of the H-metal bonds. Our contribution explores strain engineering as an effective strategy to tailor the activity of 2D mineral-based catalyst materials for HER, advancing our understanding of how mechanical manipulation can effectively modulate the catalytic properties of these materials.},
keywords = {},
pubstate = {published},
tppubtype = {misc}
}

Fechar
The catalytic properties of P t2XSe3 (X = Hg, Zn) in hydrogen-electrode- (HER-) based catalysts have been investigated based on state-of-the-art ab initio simulations. Our results show that the late transition metal sites (Hg and Zn) exhibit the best activity for HER in an acidic environment. Furthermore, lattice stretching and compression can effectively modulate the H binding energy, achieving almost thermoneutral adsorption at 3% compressive strain. The changes are attributed to the modulation in the d-band centers of late transition metal sites, as well as the depletion of charge population on bonding states, contributing to the destabilization of the H-metal bonds. Our contribution explores strain engineering as an effective strategy to tailor the activity of 2D mineral-based catalyst materials for HER, advancing our understanding of how mechanical manipulation can effectively modulate the catalytic properties of these materials.
Fechar
https://arxiv.org/abs/2505.18338
Fechar
18.
Silva, Roni A.; Batista, Gislene; Bradtmüller, Henrik; Campos, João V.; Martins, Gabriela K.; Cassar, Daniel R.; Kurelo, Bruna C. E. S.; Zallocco, Vinicius M.; Rodrigues, Ana C. M.; Cassanjes, Fabia C.; Poirier, Gael Y.; Serbena, Francisco C.
Structure–property relationships in sodium phosphate glasses and glass‐ceramics containing tantalum oxide Journal Article
Em: J Am Ceram Soc., 2025, ISSN: 1551-2916.
Resumo | Links | BibTeX | Tags:
@article{Silva2025,
title = {Structure–property relationships in sodium phosphate glasses and glass‐ceramics containing tantalum oxide},
author = {Roni A. Silva and Gislene Batista and Henrik Bradtmüller and João V. Campos and Gabriela K. Martins and Daniel R. Cassar and Bruna C. E. S. Kurelo and Vinicius M. Zallocco and Ana C. M. Rodrigues and Fabia C. Cassanjes and Gael Y. Poirier and Francisco C. Serbena},
doi = {10.1111/jace.20677},
issn = {1551-2916},
year = {2025},
date = {2025-05-20},
urldate = {2025-05-20},
journal = {J Am Ceram Soc.},
publisher = {Wiley},
abstract = {AbstractIn this study, we examine the impact of structural modifications from incorporating tantalum oxide on the thermal, electrical, and mechanical properties of sodium phosphate glasses and glass‐ceramics. Although these materials are well known for optical applications, this work aims to systematically explore their macroscopic properties, which are yet to be fully characterized. Glass samples were prepared in the binary molar system (100 − x)NaPO3–xTa2O5 with x = {20, 30, 40, 47.5, 50}. A transparent glass‐ceramic was also produced by heat‐treating the 52.5NaPO3–47.5Ta2O5 glass composition. Structural characterization was performed by Raman, Fourier transform infrared (FTIR), and solid‐state nuclear magnetic resonance (NMR) spectroscopies. Increasing tantalum oxide content led to a notable increase in glass transition temperature together with a reduced thermal stability against crystallization, indicating higher glass network connectivity at higher tantalum levels. Thermal analysis and X‐ray diffraction (XRD) confirmed the formation of a single crystalline phase in the glass‐ceramic, identified as the bronze‐like perovskite Na2Ta8O21 with an average particle size of 31 nm. Electrical properties were investigated using impedance and electric modulus formalisms, revealing that higher tantalum content increases resistivity and decreases conductivity, attributed to reduced Na+ ion concentration and increased atomic packing density. Interestingly, glass‐ceramics exhibited slightly higher conductivity than pristine glass. Density, Vickers hardness, Young's modulus, and nanoindentation hardness also increased significantly with higher tantalum content, while crystallization had a minimal effect on these properties. Overall, these results indicate that higher tantalum oxide content not only enhances the glass network's connectivity but also significantly influences the electrical and mechanical properties of sodium phosphate glasses and glass‐ceramics.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
AbstractIn this study, we examine the impact of structural modifications from incorporating tantalum oxide on the thermal, electrical, and mechanical properties of sodium phosphate glasses and glass‐ceramics. Although these materials are well known for optical applications, this work aims to systematically explore their macroscopic properties, which are yet to be fully characterized. Glass samples were prepared in the binary molar system (100 − x)NaPO3–xTa2O5 with x = {20, 30, 40, 47.5, 50}. A transparent glass‐ceramic was also produced by heat‐treating the 52.5NaPO3–47.5Ta2O5 glass composition. Structural characterization was performed by Raman, Fourier transform infrared (FTIR), and solid‐state nuclear magnetic resonance (NMR) spectroscopies. Increasing tantalum oxide content led to a notable increase in glass transition temperature together with a reduced thermal stability against crystallization, indicating higher glass network connectivity at higher tantalum levels. Thermal analysis and X‐ray diffraction (XRD) confirmed the formation of a single crystalline phase in the glass‐ceramic, identified as the bronze‐like perovskite Na2Ta8O21 with an average particle size of 31 nm. Electrical properties were investigated using impedance and electric modulus formalisms, revealing that higher tantalum content increases resistivity and decreases conductivity, attributed to reduced Na+ ion concentration and increased atomic packing density. Interestingly, glass‐ceramics exhibited slightly higher conductivity than pristine glass. Density, Vickers hardness, Young's modulus, and nanoindentation hardness also increased significantly with higher tantalum content, while crystallization had a minimal effect on these properties. Overall, these results indicate that higher tantalum oxide content not only enhances the glass network's connectivity but also significantly influences the electrical and mechanical properties of sodium phosphate glasses and glass‐ceramics.
Fechar
doi:10.1111/jace.20677
Fechar
19.
de Lima, F. Crasto; Miwa, Roberto H.; Lewenkopf, Caio; Fazzio, Adalberto
Interacting virtual topological phases in defect-rich two-dimensional materials Journal Article
Em: Phys. Rev. B, vol. 111, não 19, 2025, ISSN: 2469-9969.
Resumo | Links | BibTeX | Tags:
@article{deLima2025,
title = {Interacting virtual topological phases in defect-rich two-dimensional materials},
author = {F. Crasto de Lima and Roberto H. Miwa and Caio Lewenkopf and Adalberto Fazzio},
doi = {10.1103/physrevb.111.195135},
issn = {2469-9969},
year = {2025},
date = {2025-05-19},
urldate = {2025-05-00},
journal = {Phys. Rev. B},
volume = {111},
number = {19},
publisher = {American Physical Society (APS)},
abstract = {We investigate the robustness of virtual topological states—topological phases away from the Fermi energy—against the electron-electron interaction and band filling. As a case study, we employ a realistic model to investigate the properties of vacancy-driven topological phases in transition metal dichalcogenides (TMDs) and establish a connection between the degree of localization of topological wave functions, the vacancy density, and the electron-electron interaction strength with the topological phase robustness. We demonstrate that electron-electron interactions play a crucial role in degrading topological phases thereby determining the validity of single-particle approximations for topological insulator phases. Our findings can be naturally extended to virtual topological phases of a wide range of materials.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
We investigate the robustness of virtual topological states—topological phases away from the Fermi energy—against the electron-electron interaction and band filling. As a case study, we employ a realistic model to investigate the properties of vacancy-driven topological phases in transition metal dichalcogenides (TMDs) and establish a connection between the degree of localization of topological wave functions, the vacancy density, and the electron-electron interaction strength with the topological phase robustness. We demonstrate that electron-electron interactions play a crucial role in degrading topological phases thereby determining the validity of single-particle approximations for topological insulator phases. Our findings can be naturally extended to virtual topological phases of a wide range of materials.
Fechar
doi:10.1103/physrevb.111.195135
Fechar
20.
de Oliveira Neto, J. F.; Guimarães, F. M. A.; Dantas, Davi S.; Peeters, F. M.; Milošević, M. V.; Chaves, A.
Striped excitonic (super)solid in anisotropic semiconductors with screened exciton interactions Journal Article
Em: Phys. Rev. B, vol. 111, não 18, 2025, ISSN: 2469-9969.
Resumo | Links | BibTeX | Tags:
@article{deOliveiraNeto2025b,
title = {Striped excitonic (super)solid in anisotropic semiconductors with screened exciton interactions},
author = {J. F. de Oliveira Neto and F. M. A. Guimarães and Davi S. Dantas and F. M. Peeters and M. V. Milošević and A. Chaves},
doi = {10.1103/physrevb.111.l180506},
issn = {2469-9969},
year = {2025},
date = {2025-05-15},
urldate = {2025-05-00},
journal = {Phys. Rev. B},
volume = {111},
number = {18},
publisher = {American Physical Society (APS)},
abstract = {Within the Gross-Pitaevskii framework, we reveal the emergence of a crystallized phase of an exciton condensate in an atomically thin anisotropic semiconductor, where screening of exciton-exciton interactions is introduced by a proximal doped graphene layer. While such screened interactions are expected to yield a hexagonal crystal lattice in the excitonic condensate in isotropic semiconductor quantum wells [see, e.g., M. Matuszewski et al., Phys. Rev. Lett. 108, 060401 (2012)], here, we show that, for atomically thin semiconductors with strong electronic anisotropy, such as few-layer black phosphorus, the crystallized exciton phase acquires a parallel stripe structure. The optimal conditions for the emergence of this phase as well as its coexistence with excitonic superfluidity in a striped supersolid phase are identified.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Within the Gross-Pitaevskii framework, we reveal the emergence of a crystallized phase of an exciton condensate in an atomically thin anisotropic semiconductor, where screening of exciton-exciton interactions is introduced by a proximal doped graphene layer. While such screened interactions are expected to yield a hexagonal crystal lattice in the excitonic condensate in isotropic semiconductor quantum wells [see, e.g., M. Matuszewski et al., Phys. Rev. Lett. 108, 060401 (2012)], here, we show that, for atomically thin semiconductors with strong electronic anisotropy, such as few-layer black phosphorus, the crystallized exciton phase acquires a parallel stripe structure. The optimal conditions for the emergence of this phase as well as its coexistence with excitonic superfluidity in a striped supersolid phase are identified.
Fechar
doi:10.1103/physrevb.111.l180506
Fechar
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