Professor Pedro Autreto

@article{Khatun2024,

title = {Solid State Reaction Epitaxy, A New Approach for Synthesizing Van der Waals heterolayers: The Case of Mn and Cr on Bi_{2}Se_{3}},

author = {Salma Khatun and Onyedikachi Alanwoko and Vimukthi Pathirage and Caique C. de Oliveira and Raphael M. Tromer and Pedro A. S. Autreto and Douglas S. Galvao and Matthias Batzill},

doi = {10.1002/adfm.202315112},

issn = {1616-3028},

year  = {2024},

date = {2024-03-12},

urldate = {2024-03-12},

journal = {Adv Funct Materials},

publisher = {Wiley},

abstract = {AbstractVan der Waals (vdW) heterostructures that pair materials with diverse properties enable various quantum phenomena. However, the direct growth of vdW heterostructures is challenging. Modification of the surface layer of quantum materials to introduce new properties is an alternative process akin to solid state reaction. Here, vapor deposited transition metals (TMs), Cr and Mn, are reacted with Bi2Se3 with the goal to transform the surface layer to XBi2Se4 (X = Cr, Mn). Experiments and ab initio MD simulations demonstrate that the TMs have a high selenium affinity driving Se diffusion toward the TM. For monolayer Cr, the surface Bi2Se3 is reduced to Bi2‐layer and a stable (pseudo) 2D Cr1+δSe2 layer is formed. In contrast, monolayer Mn can transform upon mild annealing into MnBi2Se4. This phase only forms for a precise amount of initial Mn deposition. Sub‐monolayer amounts dissolve into the bulk, and multilayers form stable MnSe adlayers. This study highlights the delicate energy balance between adlayers and desired surface modified layers that governs the interface reactions and that the formation of stable adlayers can prevent the reaction with the substrate. The success of obtaining MnBi2Se4 points toward an approach for the engineering of other multicomponent vdW materials by surface reactions.},

keywords = {Biomaterials, Condensed Matter Physics, Electrochemistry, Electronic, Optical and Magnetic Materials},

pubstate = {published},

tppubtype = {article}

}

@article{Mahapatra2023,

title = {Paramagnetic two-dimensional silicon-oxide from natural silicates},

author = {Preeti Lata Mahapatra and Caique Campos de Oliveira and Gelu Costin and Suman Sarkar and Pedro A. S. Autreto and Chandra Sekhar Tiwary},

url = {https://iopscience.iop.org/article/10.1088/2053-1583/ad10b9/meta},

doi = {10.1088/2053-1583/ad10b9},

issn = {2053-1583},

year  = {2023},

date = {2023-12-12},

urldate = {2024-01-01},

journal = {2D Mater.},

volume = {11},

number = {1},

publisher = {IOP Publishing},

abstract = {Abstract

               Silicon dioxide’s potential for having magnetic properties is fascinating, as combining its electronic capabilities with magnetic response seems promising for spintronics. In this work, the mechanisms that drive the change from diamagnetic behavior in pure silicates like SiO2 to paramagnetic behavior in transition metal-doped silicates like Rhodonite silicate (CaMn3Mn(Si5O15)) are explored. This naturally occurring Rhodonite (R)-silicate was thinned down while retaining its magnetic properties by liquid-phase scalable exfoliation. Exfoliating R-silicate into the two-dimensional (2D) structure by LPE increases magnetic coercivity, and the internal resistance to demagnetization (ΔHc) up to ∼23.95 Oe compared to 7.08 Oe for its bulk phase. DFT spin-polarized calculations corroborate those findings and explain that the origin of the magnetic moment comes mainly from the Mn in the doped 2D silicate due to the asymmetrical components of the Mn d and Si p states in the valence band. This result is further illustrated by the spin component differential charge densities showing that Mn and Si atoms display a residual up spin charge. Rhodonite’s unusual magnetic behavior has considerable potential for spintronics, data storage, and sensing technologies. Understanding the complex relationships between the structural, magnetic, and electronic properties of silicates is essential for developing new materials and composites as well as for driving future research.},

keywords = {Condensed Matter Physics, General Chemistry, General Materials Science, Mechanical Engineering, Mechanics of Materials},

pubstate = {published},

tppubtype = {article}

}

@article{DeSousa2023,

title = {Boron nitride nanotube peapods at ultrasonic velocity impacts: a fully atomistic molecular dynamics investigation},

author = {J M De Sousa and L D Machado and C F Woellner and M Medina and Pedro A. S. Autreto and D S Galvão},

doi = {10.1088/1361-648x/acd50b},

issn = {1361-648X},

year  = {2023},

date = {2023-08-23},

urldate = {2023-08-23},

journal = {J. Phys.: Condens. Matter},

volume = {35},

number = {33},

publisher = {IOP Publishing},

abstract = {Abstract

               Boron nitride nanotube peapods (BNNT-peapod) are composed of linear chains of C60 molecules encapsulated inside BNNTs, they were first synthesized in 2003. In this work, we investigated the mechanical response and fracture dynamics of BNNT-peapods under ultrasonic velocity impacts (from 1 km s−1 up to 6 km s−1) against a solid target. We carried out fully atomistic reactive molecular dynamics simulations using a reactive force field. We have considered the case of horizontal and vertical shootings. Depending on the velocity values, we observed tube bending, tube fracture, and C60 ejection. Furthermore, the nanotube unzips for horizontal impacts at certain speeds, forming bi-layer nanoribbons ‘incrusted’ with C60 molecules. The methodology used here is applicable to other nanostructures. We hope it motivates other theoretical investigations on the behavior of nanostructures at ultrasonic velocity impacts and aid in interpreting future experimental results. It should be stressed that similar experiments and simulations were carried out on carbon nanotubes trying to obtain nanodiamonds. The present study expands these investigations to include BNNT.},

keywords = {Condensed Matter Physics, General Materials Science},

pubstate = {published},

tppubtype = {article}

}

@article{Oliveira2023b,

title = {Optimized 2D nanostructures for catalysis of hydrogen evolution reactions},

author = {Caique Campos de Oliveira and Pedro A. S. Autreto},

doi = {10.1557/s43580-023-00549-7},

issn = {2059-8521},

year  = {2023},

date = {2023-06-00},

urldate = {2023-06-00},

journal = {MRS Advances},

volume = {8},

number = {6},

pages = {307--310},

publisher = {Springer Science and Business Media LLC},

keywords = {Condensed Matter Physics, General Materials Science, Mechanical Engineering, Mechanics of Materials},

pubstate = {published},

tppubtype = {article}

}