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

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1.
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
2.
Oliveira, P. R. A; Lima, L.; Felix, G.; Venezuela, Pedro; Stavale, F.
Formation mechanism, stability and role of zinc and sulfur vacancies on the electronic properties and optical response of ZnS Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{deoliveira2025formationmechanismstabilityrole,
title = {Formation mechanism, stability and role of zinc and sulfur vacancies on the electronic properties and optical response of ZnS},
author = {P. R. A Oliveira and L. Lima and G. Felix and Pedro Venezuela and F. Stavale},
url = {https://arxiv.org/abs/2502.15670},
year = {2025},
date = {2025-02-21},
urldate = {2025-01-01},
abstract = {Combining experimental and theoretical tools, we report that Zn vacanciesplay an important role in the electronic and optical responses of ZnS sphalerite. The defective surface of ZnS (001) single crystal prepared in ultra-highvacuum conditions, has been shown to exhibit a semiconducting character instead of the insulating properties of the pristine structure, as revealed by X-ray photoelectron spectroscopy (XPS). Interestingly, this effect is attributed to the formation of zinc vacancies in the ZnS system, which also alter the optical response of the material, as supported by photoluminescence (PL) measurements comparing pristine and S-rich (Zn-poor) ZnS. To address these findings from a theoretical point of view, first principles calculations based on density functional theory (DFT) were performed. The optical properties of cation-defective ZnS were evaluated using random-phase approximation and hybrid functional DFT calculations. These calculations revealed absorption peaks in the visible range in the defective ZnS rather than solely in the ultra-violet range obtained for defect-free ZnS. The combination of this finding with joint density of states (JDOS) analysis explains the emergence of new luminescence peaks observed in the PL spectra of cation-defective ZnS. These findings highlight the role of Zn vacancies in tuning ZnS optical properties, making it a potential candidate for optoelectronic applications such as LEDs and photodetectors.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
Combining experimental and theoretical tools, we report that Zn vacanciesplay an important role in the electronic and optical responses of ZnS sphalerite. The defective surface of ZnS (001) single crystal prepared in ultra-highvacuum conditions, has been shown to exhibit a semiconducting character instead of the insulating properties of the pristine structure, as revealed by X-ray photoelectron spectroscopy (XPS). Interestingly, this effect is attributed to the formation of zinc vacancies in the ZnS system, which also alter the optical response of the material, as supported by photoluminescence (PL) measurements comparing pristine and S-rich (Zn-poor) ZnS. To address these findings from a theoretical point of view, first principles calculations based on density functional theory (DFT) were performed. The optical properties of cation-defective ZnS were evaluated using random-phase approximation and hybrid functional DFT calculations. These calculations revealed absorption peaks in the visible range in the defective ZnS rather than solely in the ultra-violet range obtained for defect-free ZnS. The combination of this finding with joint density of states (JDOS) analysis explains the emergence of new luminescence peaks observed in the PL spectra of cation-defective ZnS. These findings highlight the role of Zn vacancies in tuning ZnS optical properties, making it a potential candidate for optoelectronic applications such as LEDs and photodetectors.
Fechar
https://arxiv.org/abs/2502.15670
Fechar
3.
Cysne, Tarik P.; Canonico, Luis M.; Costa, Marcio; Muniz, R. B.; Rappoport, Tatiana G.
Orbitronics in Two-dimensional Materials Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{cysne2025orbitronicstwodimensionalmaterials,
title = {Orbitronics in Two-dimensional Materials},
author = {Tarik P. Cysne and Luis M. Canonico and Marcio Costa and R. B. Muniz and Tatiana G. Rappoport},
url = {https://arxiv.org/abs/2502.12339},
year = {2025},
date = {2025-02-17},
urldate = {2025-01-01},
abstract = {Orbitronics explores the control and manipulation of electronic orbital angular momentum in solid-state systems, opening new pathways for information processing and storage. One significant advantage of orbitronics over spintronics is that it does not rely on spin-orbit coupling, thereby broadening the range of non-magnetic materials that can be utilized for these applications. It also introduces new topological features related to electronic orbital angular momentum, and clarifies some long-standing challenges in understanding experiments that rely on the conventional concept of valley transport. This review highlights recent advances in orbitronics, particularly in relation to two-dimensional materials. We examine the fundamental principles underlying the generation, transport, and dynamics of orbital angular momentum to illustrate how the unique properties of two-dimensional materials can promote orbitronic phenomena. We also outline potential future research directions and address some outstanding questions in this field.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
Orbitronics explores the control and manipulation of electronic orbital angular momentum in solid-state systems, opening new pathways for information processing and storage. One significant advantage of orbitronics over spintronics is that it does not rely on spin-orbit coupling, thereby broadening the range of non-magnetic materials that can be utilized for these applications. It also introduces new topological features related to electronic orbital angular momentum, and clarifies some long-standing challenges in understanding experiments that rely on the conventional concept of valley transport. This review highlights recent advances in orbitronics, particularly in relation to two-dimensional materials. We examine the fundamental principles underlying the generation, transport, and dynamics of orbital angular momentum to illustrate how the unique properties of two-dimensional materials can promote orbitronic phenomena. We also outline potential future research directions and address some outstanding questions in this field.
Fechar
https://arxiv.org/abs/2502.12339
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4.
Cardias, R.; Bergman, Anders; Strand, Hugo U. R.; Muniz, R. B.; Costa, Marcio
Edge non-collinear magnetism in nanoribbons of Fe3GeTe2 and Fe3GaTe2 Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{cardias2025edgenoncollinearmagnetismnanoribbons,
title = {Edge non-collinear magnetism in nanoribbons of Fe3GeTe2 and Fe3GaTe2},
author = {R. Cardias and Anders Bergman and Hugo U. R. Strand and R. B. Muniz and Marcio Costa},
url = {https://arxiv.org/abs/2502.12356},
year = {2025},
date = {2025-02-17},
urldate = {2025-01-01},
abstract = {Fe3GeTe2 and Fe3GaTe2 are ferromagnetic conducting materials of van der Waals-type with unique magnetic properties that are highly promising for the development of new spintronic, orbitronic and magnonic devices. Even in the form of two-dimensional-like ultrathin films, they exhibit relatively high Curie temperature, magnetic anisotropy perpendicular to the atomic planes and multiple types of Hall effects. We explore nanoribbons made from single layers of these materials and show that they display non-collinear magnetic ordering at their edges. This magnetic inhomogeneity allows angular momentum currents to generate magnetic torques at the sample edges, regardless of their polarization direction, significantly enhancing the effectiveness of magnetization manipulation in these systems. We also demonstrate that it is possible to rapidly reverse the magnetization direction of these nanostructures by means of spin-orbit and spin-transfer torques with rather low current densities, making them quite propitious for non-volatile magnetic memory units.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
Fe3GeTe2 and Fe3GaTe2 are ferromagnetic conducting materials of van der Waals-type with unique magnetic properties that are highly promising for the development of new spintronic, orbitronic and magnonic devices. Even in the form of two-dimensional-like ultrathin films, they exhibit relatively high Curie temperature, magnetic anisotropy perpendicular to the atomic planes and multiple types of Hall effects. We explore nanoribbons made from single layers of these materials and show that they display non-collinear magnetic ordering at their edges. This magnetic inhomogeneity allows angular momentum currents to generate magnetic torques at the sample edges, regardless of their polarization direction, significantly enhancing the effectiveness of magnetization manipulation in these systems. We also demonstrate that it is possible to rapidly reverse the magnetization direction of these nanostructures by means of spin-orbit and spin-transfer torques with rather low current densities, making them quite propitious for non-volatile magnetic memory units.
Fechar
https://arxiv.org/abs/2502.12356
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5.
Goswami, Saswata; Oliveira, Caique Campos; Ipaves, Bruno; Mahapatra, Preeti Lata; Pal, Varinder; Sarkar, Suman; Autreto, Pedro A. S.; Ray, Samit K.; Tiwary, Chandra Sekhar
Exceptionally High Nonlinear Optical Response in Two-dimensional Type II Dirac Semimetal Nickel di-Telluride (NiTe2) Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{goswami2025exceptionallyhighnonlinearoptical,
title = {Exceptionally High Nonlinear Optical Response in Two-dimensional Type II Dirac Semimetal Nickel di-Telluride (NiTe2)},
author = {Saswata Goswami and Caique Campos Oliveira and Bruno Ipaves and Preeti Lata Mahapatra and Varinder Pal and Suman Sarkar and Pedro A. S. Autreto and Samit K. Ray and Chandra Sekhar Tiwary},
url = {https://arxiv.org/abs/2502.10781},
year = {2025},
date = {2025-02-15},
urldate = {2025-02-15},
abstract = {Nickel ditelluride (NiTe2) is a newly identified Type-II Dirac semimetal, showing novel characteristics in electronic transport and optical experiments. In this study, we explored the nonlinear optical properties of two-dimensional NiTe2 using experimental and computational techniques (density functional theory-based approach). Few layered two-dimensional NiTe2 (2D-NiTe2) are synthesized using liquid phase exfoliation (LPE), which is characterized using X-ray diffraction technique, transmission electron, and atomic force microscopy. The nonlinear refractive index and third-order nonlinear susceptibility of the prepared 2D-NiTe2 are determined from the self-induced diffraction pattern generated using different wavelengths ( 405, 532, and 650 nm) in the far field. In addition, the diffraction pattern generated by spatial self-phase modulation (SSPM) is further verified by varying concentration (2D-NiTe2 in the IPA solvent), wavelength (of incoming laser beams), and cuvette width (active path length). The high value of third-order nonlinear susceptibility (in order of 10-9 e.s.u.) determined using SSPM in the 2D-NiTe2 can be attributed to the laser-induced hole coherence effect. Lastly, utilizing the reverse saturable absorption property of 2D-hBN, asymmetric light propagation is also demonstrated in the 2D-NiTe2/2D-hBN heterostructure.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
Nickel ditelluride (NiTe2) is a newly identified Type-II Dirac semimetal, showing novel characteristics in electronic transport and optical experiments. In this study, we explored the nonlinear optical properties of two-dimensional NiTe2 using experimental and computational techniques (density functional theory-based approach). Few layered two-dimensional NiTe2 (2D-NiTe2) are synthesized using liquid phase exfoliation (LPE), which is characterized using X-ray diffraction technique, transmission electron, and atomic force microscopy. The nonlinear refractive index and third-order nonlinear susceptibility of the prepared 2D-NiTe2 are determined from the self-induced diffraction pattern generated using different wavelengths ( 405, 532, and 650 nm) in the far field. In addition, the diffraction pattern generated by spatial self-phase modulation (SSPM) is further verified by varying concentration (2D-NiTe2 in the IPA solvent), wavelength (of incoming laser beams), and cuvette width (active path length). The high value of third-order nonlinear susceptibility (in order of 10-9 e.s.u.) determined using SSPM in the 2D-NiTe2 can be attributed to the laser-induced hole coherence effect. Lastly, utilizing the reverse saturable absorption property of 2D-hBN, asymmetric light propagation is also demonstrated in the 2D-NiTe2/2D-hBN heterostructure.
Fechar
https://arxiv.org/abs/2502.10781
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6.
Ipaves, Bruno; Justo, João F.; de Almeida, James M.; Assali, Lucy V. C.; Autreto, Pedro A. S.
Enhancing catalyst activity of two-dimensional C4N2 through doping for the hydrogen evolution reaction Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{ipaves2025enhancingcatalystactivitytwodimensional,
title = {Enhancing catalyst activity of two-dimensional C4N2 through doping for the hydrogen evolution reaction},
author = {Bruno Ipaves and João F. Justo and James M. de Almeida and Lucy V. C. Assali and Pedro A. S. Autreto},
url = {https://arxiv.org/abs/2502.10863},
year = {2025},
date = {2025-02-15},
urldate = {2025-01-01},
abstract = {This study investigates the structural, electronic, and catalytic properties of pristine and doped C4N2 nanosheets as potential electrocatalysts for the hydrogen evolution reaction. The pristine C36N18 nanosheets exhibit limited HER activity, primarily due to high positive Gibbs free energies (> 2.2 eV). To enhance catalytic performance, doping with B, Si, or P at the nitrogen site was explored. Among these systems, B-doped C36N17 nanosheets exhibit the most promising catalytic activity, with a Gibbs free energy close to zero (≈ -0.2 eV), indicating efficient hydrogen adsorption. Band structure, projected density of states, charge density, and Bader charge analyses reveal significant changes in the electronic environment due to doping. While stacking configurations (AA′A′′ and ABC) have minimal effect on catalytic performance, doping - particularly with B -substantially alters the electronic structure, optimizing hydrogen adsorption and facilitating efficient HER. These findings suggest that B-doped C36N17 nanosheets could serve as efficient cocatalysts when combined with metallic materials, offering a promising approach to enhance catalytic efficiency in electrocatalytic and photocatalytic applications.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
This study investigates the structural, electronic, and catalytic properties of pristine and doped C4N2 nanosheets as potential electrocatalysts for the hydrogen evolution reaction. The pristine C36N18 nanosheets exhibit limited HER activity, primarily due to high positive Gibbs free energies (> 2.2 eV). To enhance catalytic performance, doping with B, Si, or P at the nitrogen site was explored. Among these systems, B-doped C36N17 nanosheets exhibit the most promising catalytic activity, with a Gibbs free energy close to zero (≈ -0.2 eV), indicating efficient hydrogen adsorption. Band structure, projected density of states, charge density, and Bader charge analyses reveal significant changes in the electronic environment due to doping. While stacking configurations (AA′A′′ and ABC) have minimal effect on catalytic performance, doping – particularly with B -substantially alters the electronic structure, optimizing hydrogen adsorption and facilitating efficient HER. These findings suggest that B-doped C36N17 nanosheets could serve as efficient cocatalysts when combined with metallic materials, offering a promising approach to enhance catalytic efficiency in electrocatalytic and photocatalytic applications.
Fechar
https://arxiv.org/abs/2502.10863
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7.
Shafiei, Mohammad; Milošević, Milorad V.
Light-induced dissipationless states in magnetic topological insulators with hexagonal warping Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{shafiei2025lightinduceddissipationlessstatesmagnetic,
title = {Light-induced dissipationless states in magnetic topological insulators with hexagonal warping},
author = {Mohammad Shafiei and Milorad V. Milošević},
url = {https://arxiv.org/abs/2502.10164},
year = {2025},
date = {2025-02-14},
urldate = {2025-01-01},
abstract = {Magnetic impurities in topological insulators (TIs) induce backscattering via magnetic torque, unlike pristine TIs where spin-orbit locking promotes dissipationless surface states. Here we reveal that one can suppress that unwanted backscattering and dissipation in magnetic TIs using high-frequency linearly polarized light (LPL). By carefully considering the hexagonal warping of the Fermi surface of the TI, we demonstrate how the coupling between Dirac surface states and LPL can effectively reduce backscattering on magnetic dopants, enhance carrier mobility and suppress resistance, even entirely. These findings open up avenues for designing ultra low-power sensing and spintronic technology.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
Magnetic impurities in topological insulators (TIs) induce backscattering via magnetic torque, unlike pristine TIs where spin-orbit locking promotes dissipationless surface states. Here we reveal that one can suppress that unwanted backscattering and dissipation in magnetic TIs using high-frequency linearly polarized light (LPL). By carefully considering the hexagonal warping of the Fermi surface of the TI, we demonstrate how the coupling between Dirac surface states and LPL can effectively reduce backscattering on magnetic dopants, enhance carrier mobility and suppress resistance, even entirely. These findings open up avenues for designing ultra low-power sensing and spintronic technology.
Fechar
https://arxiv.org/abs/2502.10164
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8.
Serquen, E.; Lizárraga, K.; Enrique, L. A.; Bravo, F.; Mishra, S.; LLontop, P.; Venezuela, Pedro; Tessler, L. R.; Guerra, J. A.
On the crystalline environment of luminescent Tb3+ ions embedded in indium tin oxide thin films: a DFT and Crystal field analysis assessment Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{serquen2025crystallineenvironmentluminescenttb3,
title = {On the crystalline environment of luminescent Tb3+ ions embedded in indium tin oxide thin films: a DFT and Crystal field analysis assessment},
author = {E. Serquen and K. Lizárraga and L. A. Enrique and F. Bravo and S. Mishra and P. LLontop and Pedro Venezuela and L. R. Tessler and J. A. Guerra},
url = {https://arxiv.org/abs/2502.08517},
doi = { https://doi.org/10.48550/arXiv.2502.08517},
year = {2025},
date = {2025-02-12},
urldate = {2025-02-12},
abstract = {We assess the local symmetry and crystal environment of trivalent terbium ions embedded in an indium tin oxide (ITO) matrix with bixbyite structure. The mbox{Tb3+} ions tend to substitute mbox{In3+} ions in two different cationic sites (b and d). Density Functional Theory (DFT) calculations suggest that the mbox{Tb3+} ions are mainly located at C2 symmetry sites relaxing selection rules and enabling electric dipole transitions, with the $^5text{D}_4rightarrowleftindex^7{text{F}}_2$ transition being the most intense, providing a red color to the light emission. Photoluminescence emission spectra under UV excitation at qty{83}{kelvin} revealed 30 intra-4f transitions, which were assigned to the $leftindex^7{text{F}}_J$ ground multiplet of the mbox{Tb3+} ion. Crystal-field analysis shows a strong alignment between calculated and observed energy levels, yielding a standard deviation of $sigma=qty{15.1}{centipermetre}$. We believe these results can help to understand the activation mechanisms of mbox{Tb3+} luminescent centers in transparent conductive oxides, as well as the potential to modulate mbox{Tb3+} emission color through its crystalline environment.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
We assess the local symmetry and crystal environment of trivalent terbium ions embedded in an indium tin oxide (ITO) matrix with bixbyite structure. The mbox{Tb3+} ions tend to substitute mbox{In3+} ions in two different cationic sites (b and d). Density Functional Theory (DFT) calculations suggest that the mbox{Tb3+} ions are mainly located at C2 symmetry sites relaxing selection rules and enabling electric dipole transitions, with the $^5text{D}_4rightarrowleftindex^7{text{F}}_2$ transition being the most intense, providing a red color to the light emission. Photoluminescence emission spectra under UV excitation at qty{83}{kelvin} revealed 30 intra-4f transitions, which were assigned to the $leftindex^7{text{F}}_J$ ground multiplet of the mbox{Tb3+} ion. Crystal-field analysis shows a strong alignment between calculated and observed energy levels, yielding a standard deviation of $sigma=qty{15.1}{centipermetre}$. We believe these results can help to understand the activation mechanisms of mbox{Tb3+} luminescent centers in transparent conductive oxides, as well as the potential to modulate mbox{Tb3+} emission color through its crystalline environment.
Fechar
https://arxiv.org/abs/2502.08517
doi: https://doi.org/10.48550/arXiv.2502.08517
Fechar
9.
Šabani, Denis; Bacaksız, Cihan; Milošević, Milorad V.
Beyond the orbitally-resolved magnetic exchange in CrI3 and NiI2 Working paper
2025.
Resumo | Links | BibTeX | Tags:
@workingpaper{šabani2025orbitallyresolvedmagneticexchangecri3,
title = {Beyond the orbitally-resolved magnetic exchange in CrI3 and NiI2},
author = {Denis Šabani and Cihan Bacaksız and Milorad V. Milošević},
url = {https://arxiv.org/abs/2502.08273},
doi = { https://doi.org/10.48550/arXiv.2502.08273},
year = {2025},
date = {2025-02-12},
urldate = {2025-02-12},
abstract = {The pertinent need for microscopic understanding of magnetic exchange motivated us to go beyond the existing theories and develop a systematic method to quantify all possible mechanisms that contribute to magnetic exchange for an arbitrary pair of atoms in a given material. We apply it to the archetypal 2D magnetic monolayers CrI3 and NiI2, to reveal the previously underrated dx2-y2,dx2-y2 contribution as either the leading or the second largest contribution to the total magnetic exchange. We proceed to explore the microscopic mechanisms behind all the non-zero orbital contributions in both CrI3 and NiI2, and generalize the findings to other magnetic monolayers dominated by d8 and d3 electronic configurations of the magnetic atoms.},
keywords = {},
pubstate = {published},
tppubtype = {workingpaper}
}

Fechar
The pertinent need for microscopic understanding of magnetic exchange motivated us to go beyond the existing theories and develop a systematic method to quantify all possible mechanisms that contribute to magnetic exchange for an arbitrary pair of atoms in a given material. We apply it to the archetypal 2D magnetic monolayers CrI3 and NiI2, to reveal the previously underrated dx2-y2,dx2-y2 contribution as either the leading or the second largest contribution to the total magnetic exchange. We proceed to explore the microscopic mechanisms behind all the non-zero orbital contributions in both CrI3 and NiI2, and generalize the findings to other magnetic monolayers dominated by d8 and d3 electronic configurations of the magnetic atoms.
Fechar
https://arxiv.org/abs/2502.08273
doi: https://doi.org/10.48550/arXiv.2502.08273
Fechar
10.
Orenstein, Rachel; Ciesielski, Kamil; Synoradzki, Karol; Qu, Jiaxing; Bipasha, Ferdaushi Alam; Gomes, Lidia C.; Adamczyk, Jesse M.; Berger, Shannon; Ertekin, Elif; Toberer, Eric S.
Complex thermoelectric transport in Bi-Sb alloys Journal Article
Em: vol. 12, não 1, 2025, ISSN: 1931-9401.
Resumo | Links | BibTeX | Tags:
@article{Orenstein2025,
title = {Complex thermoelectric transport in Bi-Sb alloys},
author = {Rachel Orenstein and Kamil Ciesielski and Karol Synoradzki and Jiaxing Qu and Ferdaushi Alam Bipasha and Lidia C. Gomes and Jesse M. Adamczyk and Shannon Berger and Elif Ertekin and Eric S. Toberer},
url = {https://pubs.aip.org/aip/apr/article-abstract/12/1/011409/3333905/Complex-thermoelectric-transport-in-Bi-Sb-alloys?redirectedFrom=fulltext},
doi = {10.1063/5.0237802},
issn = {1931-9401},
year = {2025},
date = {2025-02-05},
urldate = {2025-03-01},
volume = {12},
number = {1},
publisher = {AIP Publishing},
abstract = {Bi1−xSbx alloys are classic thermoelectric materials for near-cryogenic applications. Despite more than half a century of study, unraveling the underlying transport physics within this space has been nontrivial due to the complex electronic structure, disorder, and small bandgap within these alloys. Furthermore, as Peltier coolers, Bi1−xSbx alloys operate in a bipolar regime; as such, understanding the impact of minority carriers is critical for further improvements in device performance. This study unites first principles calculations with low-temperature experimental measurements to create a generalized model for transport within semiconducting Bi-Sb alloys. Our exploration reveals the interplay between the complex, degenerate valence band structure with the extremely light conduction bands. By building a hybrid computational/experimental model, an understanding of both the electron and hole relaxation times emerges both as a function of temperature and energy. Special quasi-random supercell calculations reveal that, despite significant atomic disorder, the electronic band structures within the alloy remains largely unaffected and electron–phonon scattering dominates. For charge carriers near the band edges, the relaxation times are thus extremely long, consistent with cyclotronic behavior appearing at low magnetic fields (≪ 1 T). Modeling thermoelectric performance suggests that the valence band edge deformation potential is significantly weaker and highlights the potential for p-type compositions to meet or exceed the current n-type alloys.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Bi1−xSbx alloys are classic thermoelectric materials for near-cryogenic applications. Despite more than half a century of study, unraveling the underlying transport physics within this space has been nontrivial due to the complex electronic structure, disorder, and small bandgap within these alloys. Furthermore, as Peltier coolers, Bi1−xSbx alloys operate in a bipolar regime; as such, understanding the impact of minority carriers is critical for further improvements in device performance. This study unites first principles calculations with low-temperature experimental measurements to create a generalized model for transport within semiconducting Bi-Sb alloys. Our exploration reveals the interplay between the complex, degenerate valence band structure with the extremely light conduction bands. By building a hybrid computational/experimental model, an understanding of both the electron and hole relaxation times emerges both as a function of temperature and energy. Special quasi-random supercell calculations reveal that, despite significant atomic disorder, the electronic band structures within the alloy remains largely unaffected and electron–phonon scattering dominates. For charge carriers near the band edges, the relaxation times are thus extremely long, consistent with cyclotronic behavior appearing at low magnetic fields (≪ 1 T). Modeling thermoelectric performance suggests that the valence band edge deformation potential is significantly weaker and highlights the potential for p-type compositions to meet or exceed the current n-type alloys.
Fechar
https://pubs.aip.org/aip/apr/article-abstract/12/1/011409/3333905/Complex-thermo[…]
doi:10.1063/5.0237802
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11.
Rajeev, Karthik; Ipaves, Bruno; de Oliveira, Caique Campos; Raman, Sreeram Punathil; Kar, Swastik; Galvao, Douglas S; Autreto, Pedro A. S.; Tiwary, Chandra Sekhar
Enhanced Non‐Invasive Radio Frequency Heating Using 2D Pyrite (Pyritene) Journal Article
Em: Small Methods, 2025, ISSN: 2366-9608.
Resumo | Links | BibTeX | Tags:
@article{Rajeev2025,
title = {Enhanced Non‐Invasive Radio Frequency Heating Using 2D Pyrite (Pyritene)},
author = {Karthik Rajeev and Bruno Ipaves and Caique Campos de Oliveira and Sreeram Punathil Raman and Swastik Kar and Douglas S Galvao and Pedro A. S. Autreto and Chandra Sekhar Tiwary},
url = {https://onlinelibrary.wiley.com/doi/10.1002/smtd.202402066},
doi = {10.1002/smtd.202402066},
issn = {2366-9608},
year = {2025},
date = {2025-02-05},
urldate = {2025-02-05},
journal = {Small Methods},
publisher = {Wiley},
abstract = {Radiofrequency (RF) heating is a new, less invasive alternative to invasive heating methods that use nanoparticles for tumour therapy. But pinpoint local heating is still hard. Molecular interactions form a hybrid structure with unique electrical characteristics that enable RF heating in this work, which explores RF heating in a biological cell (yeast)‐2D FeS2 system. Substantial processes have been uncovered via experimental investigations and density functional theory (DFT) computations. At 3 W and 50 MHz, RF heating reaches 54°C in 40 s, which is enough to kill yeast cells, while current‐voltage measurements reveal ionic diode‐like properties. Interactions between yeast lipid molecules and 2D FeSk, as shown by density‐functional theory calculations, cause an imbalance in the distribution of charges and the creation of polar, conductive channels. Insights into biological heating applications based on radio frequency (RF) technology are offered by this work, which lays forth a framework for investigating 2D material‐biomolecule interactions.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Radiofrequency (RF) heating is a new, less invasive alternative to invasive heating methods that use nanoparticles for tumour therapy. But pinpoint local heating is still hard. Molecular interactions form a hybrid structure with unique electrical characteristics that enable RF heating in this work, which explores RF heating in a biological cell (yeast)‐2D FeS2 system. Substantial processes have been uncovered via experimental investigations and density functional theory (DFT) computations. At 3 W and 50 MHz, RF heating reaches 54°C in 40 s, which is enough to kill yeast cells, while current‐voltage measurements reveal ionic diode‐like properties. Interactions between yeast lipid molecules and 2D FeSk, as shown by density‐functional theory calculations, cause an imbalance in the distribution of charges and the creation of polar, conductive channels. Insights into biological heating applications based on radio frequency (RF) technology are offered by this work, which lays forth a framework for investigating 2D material‐biomolecule interactions.
Fechar
https://onlinelibrary.wiley.com/doi/10.1002/smtd.202402066
doi:10.1002/smtd.202402066
Fechar
12.
Meydando, Taher; Abdolhosseinzadeh, Amir; Goktepe, Emine; Milošević, Milorad V.; Donmezer, Nazli
Laser-induced thermal size effects in micro-Raman thermal conductivity measurements Journal Article
Em: vol. 126, não 5, 2025, ISSN: 1077-3118.
Resumo | Links | BibTeX | Tags:
@article{Meydando2025,
title = {Laser-induced thermal size effects in micro-Raman thermal conductivity measurements},
author = {Taher Meydando and Amir Abdolhosseinzadeh and Emine Goktepe and Milorad V. Milošević and Nazli Donmezer},
url = {https://pubs.aip.org/aip/apl/article-abstract/126/5/052203/3333631/Laser-induced-thermal-size-effects-in-micro-Raman?redirectedFrom=fulltext},
doi = {10.1063/5.0250249},
issn = {1077-3118},
year = {2025},
date = {2025-02-04},
urldate = {2025-02-03},
volume = {126},
number = {5},
publisher = {AIP Publishing},
abstract = {Thermal conductivity measurements of submicrometer structures are at the core of the efficient power design of semiconductor devices. Micro-Raman spectroscopy measures thermal conductivity in a fast, nondestructive, and non-contact manner. However, the focused laser heating in micro-Raman experiments may cause drastic thermal size effects. To date, the role of such effects in the accuracy and limitations of the measurement has not been addressed. Here, we present an advanced thermal model to capture the role of material properties, laser power, and film thickness in the thermal size effects, based on the three-dimensional (3D) gray phonon Boltzmann transport equation. Recalling that laser-induced thermal size effects can lead to unexpectedly high local temperatures, even damaging the measured materials, our advanced 3D model gains particular importance for the accurate measurements of directional thermal conductivities in submicrometer structures using future high-resolution optical pump–probe techniques.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Thermal conductivity measurements of submicrometer structures are at the core of the efficient power design of semiconductor devices. Micro-Raman spectroscopy measures thermal conductivity in a fast, nondestructive, and non-contact manner. However, the focused laser heating in micro-Raman experiments may cause drastic thermal size effects. To date, the role of such effects in the accuracy and limitations of the measurement has not been addressed. Here, we present an advanced thermal model to capture the role of material properties, laser power, and film thickness in the thermal size effects, based on the three-dimensional (3D) gray phonon Boltzmann transport equation. Recalling that laser-induced thermal size effects can lead to unexpectedly high local temperatures, even damaging the measured materials, our advanced 3D model gains particular importance for the accurate measurements of directional thermal conductivities in submicrometer structures using future high-resolution optical pump–probe techniques.
Fechar
https://pubs.aip.org/aip/apl/article-abstract/126/5/052203/3333631/Laser-induced[…]
doi:10.1063/5.0250249
Fechar
13.
Damasceno, Daniela A.; Hue, Keat Yung; Miranda, Caetano R.; Müller, Erich A.
Mechanical Properties of Polyethylene/Carbon Nanotube Composites from Coarse-Grained Simulations Journal Article
Em: Nanomaterials, vol. 15, não 3, 2025, ISSN: 2079-4991.
Resumo | Links | BibTeX | Tags:
@article{Damasceno2025,
title = {Mechanical Properties of Polyethylene/Carbon Nanotube Composites from Coarse-Grained Simulations},
author = {Daniela A. Damasceno and Keat Yung Hue and Caetano R. Miranda and Erich A. Müller},
url = {https://www.mdpi.com/2079-4991/15/3/200},
doi = {10.3390/nano15030200},
issn = {2079-4991},
year = {2025},
date = {2025-01-27},
urldate = {2025-02-00},
journal = {Nanomaterials},
volume = {15},
number = {3},
publisher = {MDPI AG},
abstract = {Advanced nanocomposite membranes incorporate nanomaterials within a polymer matrix to augment the mechanical strength of the resultant product. Characterizing these membranes through molecular modeling necessitates specialized approaches to accurately capture the length scales, time scales, and structural complexities inherent in polymers. To address these requirements, an efficient simulation protocol is proposed, utilizing coarse-grained (CG) molecular dynamics simulations to examine the mechanical properties of polyethylene/single-walled carbon nanotube (PE/SWCNT) composites. This methodology integrates CG potentials derived from the statistical associating fluid theory (SAFT-γ Mie) equation of state and a modified Tersoff potential as a model for SWCNTs. A qualitative correspondence with benchmark classical all-atom models, as well as available experimental data, is observed, alongside enhanced computational efficiency. Employing this CG model, the focus is directed at exploring the mechanical properties of PE/SWCNT composites under both tensile and compressive loading conditions. The investigation covered the influence of SWCNT size, dispersion, and weight fraction. The findings indicate that although SWCNTs enhance the mechanical strength of PE, the extent of enhancement marginally depends on the dispersion, filler size, and weight fraction. Fracture strengths may be elevated by 20% with a minor incorporation of SWCNTs. Under compression, the incorporation of SWCNTs into the composites results in a transformation from brittle to tough materials. These insights contribute to the optimization of PE/SWCNT composites, emphasizing the importance of considering multiple factors to fine-tune the desired mechanical performance.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Advanced nanocomposite membranes incorporate nanomaterials within a polymer matrix to augment the mechanical strength of the resultant product. Characterizing these membranes through molecular modeling necessitates specialized approaches to accurately capture the length scales, time scales, and structural complexities inherent in polymers. To address these requirements, an efficient simulation protocol is proposed, utilizing coarse-grained (CG) molecular dynamics simulations to examine the mechanical properties of polyethylene/single-walled carbon nanotube (PE/SWCNT) composites. This methodology integrates CG potentials derived from the statistical associating fluid theory (SAFT-γ Mie) equation of state and a modified Tersoff potential as a model for SWCNTs. A qualitative correspondence with benchmark classical all-atom models, as well as available experimental data, is observed, alongside enhanced computational efficiency. Employing this CG model, the focus is directed at exploring the mechanical properties of PE/SWCNT composites under both tensile and compressive loading conditions. The investigation covered the influence of SWCNT size, dispersion, and weight fraction. The findings indicate that although SWCNTs enhance the mechanical strength of PE, the extent of enhancement marginally depends on the dispersion, filler size, and weight fraction. Fracture strengths may be elevated by 20% with a minor incorporation of SWCNTs. Under compression, the incorporation of SWCNTs into the composites results in a transformation from brittle to tough materials. These insights contribute to the optimization of PE/SWCNT composites, emphasizing the importance of considering multiple factors to fine-tune the desired mechanical performance.
Fechar
https://www.mdpi.com/2079-4991/15/3/200
doi:10.3390/nano15030200
Fechar
14.
Scopel, Wanderlã L.; de Souza, Fábio A. L.; de Souza, Sávio Bastos; Amorim, Rodrigo G.; Scheicher, Ralph H
Computational simulation of graphene/h-BN nanopores for single-molecule herbicide sensing Journal Article
Em: Nanotechnology, 2025, ISSN: 1361-6528.
Resumo | Links | BibTeX | Tags:
@article{Scopel2025,
title = {Computational simulation of graphene/h-BN nanopores for single-molecule herbicide sensing},
author = {Wanderlã L. Scopel and Fábio A. L. de Souza and Sávio Bastos de Souza and Rodrigo G. Amorim and Ralph H Scheicher},
url = {https://pubs.rsc.org/th/content/articlelanding/2025/nr/d4nr03359k},
doi = {10.1088/1361-6528/adac67},
issn = {1361-6528},
year = {2025},
date = {2025-01-21},
urldate = {2025-01-21},
journal = {Nanotechnology},
publisher = {IOP Publishing},
abstract = {The growing world population and climate change are key drivers for the increasing pursuit of more efficient and environmentally-safe food production. In this scenario, the large scale use of herbicides demands the development new technologies to control and monitor the application of these compounds, due to their several environmental and health-related problems. Motivated by all these issues, in this work, a hybrid graphene/boron nitride nanopore is explore to detect/identify herbicide molecules (Glyphosate, AMPA, Diuron, and 2,4-D). Solid-state nanopores based on 2D materials have been widely explored as novel generation sensors capable of single-molecule resolution. The present investigation combines the density functional theory (DFT) and non-equilibrium Green’s function (NEGF) method to assess the interaction of each herbicide with the nanopore and how its interaction modulates the device’s electronic transport properties. The device’s sensitivity spreads from 9.0 up to 27.0% when probed at different gate voltage values. Overall, the proposed device seems to be sensitive and selective to be considered as a promising single-molecule herbicide sensor.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
The growing world population and climate change are key drivers for the increasing pursuit of more efficient and environmentally-safe food production. In this scenario, the large scale use of herbicides demands the development new technologies to controland monitor the application of these compounds, due to their several environmental and health-related problems. Motivated by all these issues, in this work, a hybrid graphene/boron nitride nanopore is explore to detect/identify herbicide molecules (Glyphosate, AMPA, Diuron, and 2,4-D). Solid-state nanopores based on 2D materials have been widely explored as novel generation sensors capable of single-molecule resolution. The present investigation combines the density functional theory (DFT) and non-equilibrium Green’s function (NEGF) method to assess the interaction of each herbicide with the nanopore and how its interaction modulates the device’s electronictransport properties. The device’s sensitivity spreads from 9.0 up to 27.0% when probed at different gate voltage values. Overall, the proposed device seems to be sensitive and selective to be considered as a promising single-molecule herbicide sensor.
Fechar
https://pubs.rsc.org/th/content/articlelanding/2025/nr/d4nr03359k
doi:10.1088/1361-6528/adac67
Fechar
15.
Brandão, Jeovani; Carvalho, Pamela C.; Miranda, Ivan P.; Mori, Thiago J. A.; Béron, Fanny; Bergman, Anders; Petrilli, Helena M.; Klautau, Angela B.; Cezar, Julio C.
Proximity-induced flipped spin state in synthetic ferrimagnetic Pt/Co/Gd heterolayers Journal Article
Em: Commun Phys, vol. 8, não 1, 2025, ISSN: 2399-3650.
Resumo | Links | BibTeX | Tags:
@article{Brandão2025,
title = {Proximity-induced flipped spin state in synthetic ferrimagnetic Pt/Co/Gd heterolayers},
author = {Jeovani Brandão and Pamela C. Carvalho and Ivan P. Miranda and Thiago J. A. Mori and Fanny Béron and Anders Bergman and Helena M. Petrilli and Angela B. Klautau and Julio C. Cezar},
url = {https://www.nature.com/articles/s42005-025-01938-0},
doi = {10.1038/s42005-025-01938-0},
issn = {2399-3650},
year = {2025},
date = {2025-01-15},
urldate = {2025-12-00},
journal = {Commun Phys},
volume = {8},
number = {1},
publisher = {Springer Science and Business Media LLC},
abstract = {To develop new devices based on synthetic ferrimagnetic heterostructures, understanding the material’s physical properties is pivotal. Here, the induced magnetic moment (IMM), magnetic exchange coupling, and spin textures are investigated in Pt(1 nm)/Co(1.5 nm)/Gd(1 nm) multilayers using a multiscale approach. The magnitude and direction of the IMM are interpreted in the framework of both X-ray magnetic circular dichroism and density functional theory. The IMM transferred by Co across the Gd paramagnetic thickness leads to a nontrivial flipped spin state (FSS) within the Gd layers, in which their magnetic moments couple antiparallel/parallel with the ferromagnetic Co near/far from the Co/Gd interface, respectively. The FSS depends on the magnetic field, which, on average, reduces the Gd magnetic moment as the field increases. For the Pt, in both Pt/Co and Gd/Pt interfaces, the IMM follows the same direction as the Co magnetic moment, with negligible IMM in the Gd/Pt interface. Additionally, zero-field spin spirals were imaged using scanning transmission X-ray microscopy, whereas micromagnetic simulations were employed to unfold the interactions, stabilizing the ferrimagnetic configurations, where the existence of a sizable Dzyaloshinskii-Moriya interaction is demonstrated to be crucial.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
To develop new devices based on synthetic ferrimagnetic heterostructures, understanding the material’s physical properties is pivotal. Here, the induced magnetic moment (IMM), magnetic exchange coupling, and spin textures are investigated in Pt(1 nm)/Co(1.5 nm)/Gd(1 nm) multilayers using a multiscale approach. The magnitude and direction of the IMM are interpreted in the framework of both X-ray magnetic circular dichroism and density functional theory. The IMM transferred by Co across the Gd paramagnetic thickness leads to a nontrivial flipped spin state (FSS) within the Gd layers, in which their magnetic moments couple antiparallel/parallel with the ferromagnetic Co near/far from the Co/Gd interface, respectively. The FSS depends on the magnetic field, which, on average, reduces the Gd magnetic moment as the field increases. For the Pt, in both Pt/Co and Gd/Pt interfaces, the IMM follows the same direction as the Co magnetic moment, with negligible IMM in the Gd/Pt interface. Additionally, zero-field spin spirals were imaged using scanning transmission X-ray microscopy, whereas micromagnetic simulations were employed to unfold the interactions, stabilizing the ferrimagnetic configurations, where the existence of a sizable Dzyaloshinskii-Moriya interaction is demonstrated to be crucial.
Fechar
https://www.nature.com/articles/s42005-025-01938-0
doi:10.1038/s42005-025-01938-0
Fechar
16.
Amorim, Rodrigo G.; Lima, Filipe C. D. A.; de Souza, Fábio Arthur Leão; Scopel, Wanderlã L.; Prasongkit, Jariyanee; Scheicher, Ralph H.
Detection and distinction of amino acids and post-translational modifications with gold nanojunctions Journal Article
Em: Nanoscale, 2025, ISSN: 2040-3372.
Resumo | Links | BibTeX | Tags:
@article{Amorim2025,
title = {Detection and distinction of amino acids and post-translational modifications with gold nanojunctions},
author = {Rodrigo G. Amorim and Filipe C. D. A. Lima and Fábio Arthur Leão de Souza and Wanderlã L. Scopel and Jariyanee Prasongkit and Ralph H. Scheicher},
url = {https://pubs.rsc.org/th/content/articlelanding/2025/nr/d4nr03359k},
doi = {10.1039/d4nr03359k},
issn = {2040-3372},
year = {2025},
date = {2025-01-01},
urldate = {2025-01-01},
journal = {Nanoscale},
publisher = {Royal Society of Chemistry (RSC)},
abstract = {Amino acids are fundamental building blocks of proteins, playing critical roles in medical diagnostics, environmental monitoring, and biomarker identification. The development of nanoscale electronic sensors capable of single-amino-acid recognition has gained significant attention due to their potential for label-free, real-time detection. In this study, we investigate the electronic transport properties of amino acids in two gold-based nanodevices with distinct architectures: a gold nanojunction and a gold-capacitor system. Using density functional theory (DFT) in combination with nonequilibrium Green's function (NEGF) calculations, we explore the sensing mechanism and conductance variations induced by different amino acids, including select phosphorylated variants. Each device was assigned a reference amino acid, F (M), for a capacitor (nanojunction) to differentiate its conductance from other molecules. Our results reveal distinct conductance that enables amino acid classification based on their electronic signatures, demonstrating that molecular discrimination is primarily governed by conductance variations as a function of the binding energy differences. The nanojunction exhibited remarkable differentiation for the amino acids S, pS, Y, and pY, rendering it especially proficient in distinguishing between structurally analogous molecules. These findings highlight the strong potential of gold-based nanodevices for precise amino acid detection, paving the way for advancements in biosensing technologies, molecular diagnostics, and biomedical applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Amino acids are fundamental building blocks of proteins, playing critical roles in medical diagnostics, environmental monitoring, and biomarker identification. The development of nanoscale electronic sensors capable of single-amino-acid recognition has gained significant attention due to their potential for label-free, real-time detection. In this study, we investigate the electronic transport properties of amino acids in two gold-based nanodevices with distinct architectures: a gold nanojunction and a gold-capacitor system. Using density functional theory (DFT) in combination with nonequilibrium Green's function (NEGF) calculations, we explore the sensing mechanism and conductance variations induced by different amino acids, including select phosphorylated variants. Each device was assigned a reference amino acid, F (M), for a capacitor (nanojunction) to differentiate its conductance from other molecules. Our results reveal distinct conductance that enables amino acid classification based on their electronic signatures, demonstrating that molecular discrimination is primarily governed by conductance variations as a function of the binding energy differences. The nanojunction exhibited remarkable differentiation for the amino acids S, pS, Y, and pY, rendering it especially proficient in distinguishing between structurally analogous molecules. These findings highlight the strong potential of gold-based nanodevices for precise amino acid detection, paving the way for advancements in biosensing technologies, molecular diagnostics, and biomedical applications.
Fechar
https://pubs.rsc.org/th/content/articlelanding/2025/nr/d4nr03359k
doi:10.1039/d4nr03359k
Fechar
17.
de Lima, F. Crasto; Miwa, Roberto H.; Lewenkopf, Caio; Fazzio, Adalberto
Interacting Virtual Topological Phases in Defect-Rich 2D Materials Working paper
2024.
Resumo | Links | BibTeX | Tags:
@workingpaper{delima2024interactingvirtualtopologicalphases,
title = {Interacting Virtual Topological Phases in Defect-Rich 2D Materials},
author = {F. Crasto de Lima and Roberto H. Miwa and Caio Lewenkopf and Adalberto Fazzio},
url = {https://arxiv.org/abs/2412.08607},
year = {2024},
date = {2024-12-11},
urldate = {2024-01-01},
abstract = {We investigate the robustness of {it 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 = {workingpaper}
}

Fechar
We investigate the robustness of {it 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
https://arxiv.org/abs/2412.08607
Fechar
18.
de Freitas, Andre Luiz Martins; Caturello, Naidel A. M. S.; Tofanello, Aryane; Kaneko, Ulisses F.; Correa, Lucas E.; dos Reis, Ricardo Donizeth; Ferreira, Fabio Furlan; Dalpian, Gustavo M.; Souza, José A
Releasing trapped excitons in 2D perovskites via pressure annealing: A cooperative interplay between lattice strain and electronic structure. Journal Article
Em: Mater. Chem. Front., 2024, ISSN: 2052-1537.
Resumo | Links | BibTeX | Tags:
@article{deFreitas2025,
title = {Releasing trapped excitons in 2D perovskites via pressure annealing: A cooperative interplay between lattice strain and electronic structure.},
author = {Andre Luiz Martins de Freitas and Naidel A. M. S. Caturello and Aryane Tofanello and Ulisses F. Kaneko and Lucas E. Correa and Ricardo Donizeth dos Reis and Fabio Furlan Ferreira and Gustavo M. Dalpian and José A Souza},
url = {https://pubs.rsc.org/en/content/articlelanding/2025/qm/d4qm00780h},
doi = {10.1039/d4qm00780h},
issn = {2052-1537},
year = {2024},
date = {2024-12-11},
urldate = {2025-00-00},
journal = {Mater. Chem. Front.},
publisher = {Royal Society of Chemistry (RSC)},
abstract = {The characteristic photon emissions in low-dimensional hybrid perovskites are strongly related to inherent distortions in the crystal lattice. These cooperative distortions, influenced by organic spacers and the confined BX6 octahedra arrangement, allow for the manipulation and control of the emitted photon energy and its nature. Here, we observe a complex dynamic where photon emissions at both low and high energies emerge, depending on octahedral distortion and the application of hydrostatic pressure. Our results demonstrate that samples featuring different octahedra sizes and distortions, yet having a common organic spacer (BA2MAPb2Br7 and BA2MAPb2I7), show low-energy photon emission attributed to self-trapped excitons (STEs) which can be tuned towards to free exciton states (FE) through pressure annealing. Experimental and theoretical results revealed that octahedral distortions in 2D perovskites play a crucial role in controlling emission, disclosing their complex structure and electronic relationship.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
The characteristic photon emissions in low-dimensional hybrid perovskites are strongly related to inherent distortions in the crystal lattice. These cooperative distortions, influenced by organic spacers and the confined BX6 octahedra arrangement, allow for the manipulation and control of the emitted photon energy and its nature. Here, we observe a complex dynamic where photon emissions at both low and high energies emerge, depending on octahedral distortion and the application of hydrostatic pressure. Our results demonstrate that samples featuring different octahedra sizes and distortions, yet having a common organic spacer (BA2MAPb2Br7 and BA2MAPb2I7), show low-energy photon emission attributed to self-trapped excitons (STEs) which can be tuned towards to free exciton states (FE) through pressure annealing. Experimental and theoretical results revealed that octahedral distortions in 2D perovskites play a crucial role in controlling emission, disclosing their complex structure and electronic relationship.
Fechar
https://pubs.rsc.org/en/content/articlelanding/2025/qm/d4qm00780h
doi:10.1039/d4qm00780h
Fechar
19.
Almeida, L.; Pereira, Teldo A. S.; Lima, Erika Nascimento
Propriedades eletrônicas e topológicas do antimoneno sob efeito de tensão: uma abordagem por cálculos de primeiros princípios Journal Article
Em: JMFis, vol. 07, não 02, pp. 27–32, 2024, ISSN: 2965-1964.
Resumo | Links | BibTeX | Tags:
@article{Almeida2024,
title = {Propriedades eletrônicas e topológicas do antimoneno sob efeito de tensão: uma abordagem por cálculos de primeiros princípios},
author = {L. Almeida and Teldo A. S. Pereira and Erika Nascimento Lima},
doi = {10.59396/29651964jmfis.7-2.27.2024},
issn = {2965-1964},
year = {2024},
date = {2024-12-09},
urldate = {2024-00-00},
journal = {JMFis},
volume = {07},
number = {02},
pages = {27--32},
publisher = {Programa de Pós-Graduação em Física, Universidade Federal de Mato Grosso},
abstract = {Neste estudo, utilizamos cálculos baseados na teoria do funcional da densidade (DFT) para investigar as propriedades eletrônicas do antimoneno sob tração biaxial. Observamos que uma tensão de 2% induz uma transição de gap indireto para direto, que persiste até o fechamento do gap em 11%. Acima desse valor, o material volta a exibir gap indireto e passa a se comportar como um isolante topológico, confirmado pelo invariante Z2=1. Esses resultados demonstram a versatilidade do antimoneno e seu potencial para aplicações em nanoeletrônica e spintrônica.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Neste estudo, utilizamos cálculos baseados na teoria do funcional da densidade (DFT) para investigar as propriedades eletrônicas do antimoneno sob tração biaxial. Observamos que uma tensão de 2% induz uma transição de gap indireto para direto, que persiste até o fechamento do gap em 11%. Acima desse valor, o material volta a exibir gap indireto e passa a se comportar como um isolante topológico, confirmado pelo invariante Z2=1. Esses resultados demonstram a versatilidade do antimoneno e seu potencial para aplicações em nanoeletrônica e spintrônica.
Fechar
doi:10.59396/29651964jmfis.7-2.27.2024
Fechar
20.
da Silva Barboza, Elisangela; Dias, Alexandre C.; Craco, Luis; Carara, Sabrina S.; da Costa, Diego R.; Pereira, Teldo A. S.
Electronic, Excitonic, and Optical Properties of Zinc Blende Boron Arsenide Tuned by Hydrostatic Pressure Journal Article
Em: ACS Omega, vol. 9, não 48, pp. 47710–47718, 2024, ISSN: 2470-1343.
Resumo | Links | BibTeX | Tags:
@article{daSilvaBarboza2024,
title = {Electronic, Excitonic, and Optical Properties of Zinc Blende Boron Arsenide Tuned by Hydrostatic Pressure},
author = {Elisangela da Silva Barboza and Alexandre C. Dias and Luis Craco and Sabrina S. Carara and Diego R. da Costa and Teldo A. S. Pereira},
doi = {10.1021/acsomega.4c07598},
issn = {2470-1343},
year = {2024},
date = {2024-12-03},
urldate = {2024-12-03},
journal = {ACS Omega},
volume = {9},
number = {48},
pages = {47710--47718},
publisher = {American Chemical Society (ACS)},
abstract = {Based on first-principles calculations combined with a maximally localized Wannier function tight-binding method and the Bethe–Salpeter equation formalism, we theoretically investigate the effects of hydrostatic pressure on the electronic, excitonic, and optical properties of zinc blende boron arsenide. Our findings show: (i) a pressure-induced semiconductor-to-metallic phase transition without causing any change in the structural crystallographic ordering, (ii) a decrease in excitonic binding energy with increasing pressure as a consequence of band gap engineering, and (iii) a small excitonic response in the indirect absorption regime due to the indirect band gap.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}

Fechar
Based on first-principles calculations combined with a maximally localized Wannier function tight-binding method and the Bethe–Salpeter equation formalism, we theoretically investigate the effects of hydrostatic pressure on the electronic, excitonic, and optical properties of zinc blende boron arsenide. Our findings show: (i) a pressure-induced semiconductor-to-metallic phase transition without causing any change in the structural crystallographic ordering, (ii) a decrease in excitonic binding energy with increasing pressure as a consequence of band gap engineering, and (iii) a small excitonic response in the indirect absorption regime due to the indirect band gap.
Fechar
doi:10.1021/acsomega.4c07598
Fechar
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