Computational generation of disordered structures of Al-12%Si. An ab initio approach

AbstractMetallic glasses are in the forefront of metallurgical research and applications. For this reason it is important to realistically model amorphous metallic systems. Some computer simulation efforts have relied on the use of parameterized classical potentials of the Lennard-Jones type or geometric hard sphere simulations, but first principles approaches have been rarely used. In this work we apply our recently developed ab initio DFT approach (A. A. Valladares et al., Eur. Phys. J. 22 (2001) 443) for the generation of amorphous semiconducting materials, to amorphize an aluminum-silicon alloy, the eutectic Al-12%Si. We report specific atomic structures and radial distribution functions (RDFs), total and partial, of one amorphous and one liquid-amorphous periodic cubic supercell of 125 atoms (15 silicons and 110 aluminums), Al-12%Si, with a volume (12.8379 Å)3, generated using the Harris functional.

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Structural properties of amorphous aluminum and aluminum-nitrogen alloys. Computer simulations

MRS Proceedings ◽

10.1557/proc-848-ff9.29 ◽

2004 ◽

Vol 848 ◽

Author(s):

Ariel A. Valladares ◽

Alexander Valladares ◽

R. M. Valladares ◽

A. Calles

Keyword(s):

Physical Properties ◽

Computer Simulations ◽

First Principles ◽

Hard Sphere ◽

Distribution Functions ◽

Radial Distribution Functions ◽

Semiconducting Materials ◽

Atomic Structures ◽

Lennard Jones ◽

Nitrogen Alloy

AbstractLiquid and amorphous metallic systems have proven difficult to model. Some efforts have relied on the use of parameterized classical potentials of the Lennard-Jones type or geometric hard sphere simulations, but first principles approaches have been rarely used. Clearly a knowledge of atomic structures is paramount for calculating physical properties. In this work we apply our recently developed ab initio DFT approach (A. A. Valladares et al., Eur. Phys. J. 22 (2001) 443) for the generation of amorphous semiconducting materials, to amorphize aluminum and an aluminum-nitrogen alloy. We report radial distribution functions (RDFs) and specific atomic structures of periodic amorphous/liquid cubic supercells of 108 atoms with a volume of (12.1485 Å)3, generated using the Harris functional.

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Colour degradation of artworks: an ab initio approach to X-ray, electronic and optical spectroscopy analyses of vermilion photodarkening

Journal of Analytical Atomic Spectrometry ◽

10.1039/c4ja00327f ◽

2015 ◽

Vol 30 (3) ◽

pp. 588-598 ◽

Cited By ~ 19

Author(s):

C. Hogan ◽

F. Da Pieve

Keyword(s):

Ab Initio ◽

Optical Spectroscopy ◽

First Principles ◽

First Principles Calculations ◽

X Ray ◽

Ab Initio Approach

First principles calculations explain the presence, colour, and photo-reactivity of Hg-containing compounds involved in vermilion degradation.

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First-principles prediction of electronic transport in fabricated semiconductor heterostructures via physics-aware machine learning

npj Computational Materials ◽

10.1038/s41524-021-00562-0 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Artem K. Pimachev ◽

Sanghamitra Neogi

Keyword(s):

Machine Learning ◽

Ab Initio ◽

Electronic Transport ◽

First Principles ◽

Silicon Germanium ◽

Transport Coefficients ◽

Semiconductor Heterostructures ◽

Electronic Transport Property ◽

Atomic Structures ◽

Ab Initio Models

AbstractFirst-principles techniques for electronic transport property prediction have seen rapid progress in recent years. However, it remains a challenge to predict properties of heterostructures incorporating fabrication-dependent variability. Machine-learning (ML) approaches are increasingly being used to accelerate design and discovery of new materials with targeted properties, and extend the applicability of first-principles techniques to larger systems. However, few studies exploited ML techniques to characterize relationships between local atomic structures and global electronic transport coefficients. In this work, we propose an electronic-transport-informatics (ETI) framework that trains on ab initio models of small systems and predicts thermopower of fabricated silicon/germanium heterostructures, matching measured data. We demonstrate application of ML approaches to extract important physics that determines electronic transport in semiconductor heterostructures, and bridge the gap between ab initio accessible models and fabricated systems. We anticipate that ETI framework would have broad applicability to diverse materials classes.

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Insights of $$\hbox {XPt}_2$$ ($$\hbox {X}=\hbox {Eu}$$ and Gd) intermetallic systems: An ab-initio approach

Pramana ◽

10.1007/s12043-021-02110-3 ◽

2021 ◽

Vol 95 (2) ◽

Author(s):

Azad A Mansoori ◽

Amreen Bano

Keyword(s):

Ab Initio ◽

Ab Initio Approach

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Flexoelectricity in atomic monolayers from first principles

Nanoscale ◽

10.1039/d0nr07803d ◽

2020 ◽

Author(s):

Shashikant Kumar ◽

David Codony ◽

Irene Arias ◽

Phanish Suryanarayana

Keyword(s):

Density Functional Theory ◽

Transition Metal ◽

Ab Initio ◽

First Principles ◽

Density Functional ◽

Transition Metal Dichalcogenides ◽

Functional Theory ◽

Group Iii ◽

Flexoelectric Effect ◽

Metal Dichalcogenides

We study the flexoelectric effect in fifty-four select atomic monolayers using ab initio Density Functional Theory (DFT). Specifically, considering representative materials from each of Group III monochalcogenides, transition metal dichalcogenides...

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Li Uptake in Carbon Nanotube Systems: A First Principles Investigation

MRS Proceedings ◽

10.1557/proc-706-z8.8.1 ◽

2001 ◽

Vol 706 ◽

Author(s):

Vincent Meunier ◽

Jeremy Kephart ◽

Christopher Roland ◽

Jerry Bernholc

Keyword(s):

Carbon Nanotube ◽

Ab Initio ◽

Ball Milling ◽

First Principles ◽

Topological Defects ◽

Ion Bombardment ◽

Ion Uptake ◽

Li Ion ◽

Pass Through ◽

Non Equilibrium

AbstractCarbon nanotube systems can substantially increase their capacity for Li ion uptake, provided that the nanotube interiors become accessible to the ions. We examine theoretically, with ab initio simulations, the ability of Li ions to enter a nanotube interior. While our calculations show that it is quite unlikely for the ions to pass through pristine nanotubes, they are much more likely to enter via large-sized topological defects consisting of at least 9- or more membered rings. It is unlikely that such defects are formed spontaneously, but it may be possible to induce such topological defects by violent non-equilibrium means such as ball milling, chemical means and/or ion bombardment. Indeed, recent experiments on ball milled nanotube samples do report an important increase in the Li ion uptake.

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Computational Methods for Ab Initio Molecular Dynamics

Advances in Chemistry ◽

10.1155/2018/9839641 ◽

2018 ◽

Vol 2018 ◽

pp. 1-14 ◽

Cited By ~ 7

Author(s):

Eric Paquet ◽

Herna L. Viktor

Keyword(s):

Molecular Dynamics ◽

Quantum Mechanics ◽

Ab Initio ◽

First Principles ◽

Density Functional ◽

Path Integrals ◽

Ab Initio Molecular Dynamics ◽

Molecular Systems ◽

Hartree Fock ◽

Computational Perspective

Ab initio molecular dynamics is an irreplaceable technique for the realistic simulation of complex molecular systems and processes from first principles. This paper proposes a comprehensive and self-contained review of ab initio molecular dynamics from a computational perspective and from first principles. Quantum mechanics is presented from a molecular dynamics perspective. Various approximations and formulations are proposed, including the Ehrenfest, Born–Oppenheimer, and Hartree–Fock molecular dynamics. Subsequently, the Kohn–Sham formulation of molecular dynamics is introduced as well as the afferent concept of density functional. As a result, Car–Parrinello molecular dynamics is discussed, together with its extension to isothermal and isobaric processes. Car–Parrinello molecular dynamics is then reformulated in terms of path integrals. Finally, some implementation issues are analysed, namely, the pseudopotential, the orbital functional basis, and hybrid molecular dynamics.

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