Journal ArticleDOI
Efficient stochastic generation of special quasirandom structures
A. van de Walle,Pratyush Tiwary,M. de Jong,David L. Olmsted,Mark Asta,A. Dick,Dongwon Shin,Yi Wang,Long Qing Chen,Zi Kui Liu +9 more
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TLDR
The proposed method optimizes the shape of the supercell jointly with the occupation of the atomic sites, thus ensuring that the configurational space searched is exhaustive and not biased by a pre-specified supercell shape.Abstract:
We present a new algorithm to generate Special Quasirandom Structures (SQS), i.e., best periodic supercell approximations to the true disordered state for a given number of atoms per supercell. The method is based on a Monte Carlo simulated annealing loop with an objective function that seeks to perfectly match the maximum number of correlation functions (as opposed to merely minimizing the distance between the SQS correlation and the disordered state correlations for a pre-specified set of correlations). The proposed method optimizes the shape of the supercell jointly with the occupation of the atomic sites, thus ensuring that the configurational space searched is exhaustive and not biased by a pre-specified supercell shape. The method has been implemented in the “mcsqs” code of the Alloy Theoretic Automated Toolkit (ATAT) in the most general framework of multicomponent multisublattice systems and in a way that minimizes the amount of input information the user needs to specify and that allows for efficient parallelization.read more
Citations
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Journal ArticleDOI
Effect of ternary additions to structural properties of NiTi alloys
Navdeep Singh,Anjana Talapatra,Anchalee Junkaew,Thien Duong,Sean Gibbons,Shengyen Li,Hassan S. Thawabi,Emmi Olivos,Raymundo Arroyave +8 more
TL;DR: In this paper, the effects of small ternary additions to B2 NiTi structures through DFT calculations were investigated through deviations from stoichiometry arising from either simple substitution of host atoms in a given sublattice or from the formation of anti-sites.
Journal ArticleDOI
Alloy-Free Band Gap Tuning across the Visible Spectrum.
Robert A. Makin,Krystal York,Steven M. Durbin,Nancy Senabulya,James Mathis,Roy Clarke,Nathaniel Feldberg,Patrice Miska,Christina M. Jones,Zihao Deng,Logan Williams,Emmanouil Kioupakis,Roger J. Reeves +12 more
TL;DR: The results clearly demonstrate the correlation between controlled heterovalent cation ordering and the optical band gap, which applies to a broad group of emerging ternaryheterovalent compounds and has implications for similar trends in other material properties besides the band gap.
Journal ArticleDOI
Density functional theory + U analysis of the electronic structure and defect chemistry of LSCF (La0.5Sr0.5Co0.25Fe0.75O3−δ)
TL;DR: Results show that compositions with more Fe than Co are preferred because the additional sites would lead to higher overall ΔEf,vac (and lower concentrations), while the trapping strength of the sites is relatively weak (∼0.3 eV).
Journal ArticleDOI
Vacancy-dependent stability of cubic and wurtzite Ti1−xAlxN
Holger Euchner,Paul H. Mayrhofer +1 more
TL;DR: By means of density functional theory, it is shown that vacancies on metal and/or non-metal sites only slightly affect the cubic to wurtzite transition region, whereas they clearly affect the physical properties.
Journal ArticleDOI
Band gap bowing in NixMg1-xO.
Christian A. Niedermeier,Mikael Råsander,Sneha Rhode,Vyacheslav Kachkanov,Bin Zou,Neil McN. Alford,Michelle A. Moram +6 more
TL;DR: Density functional calculations of the NixMg1−xO band structure and the density of states demonstrate that deep Ni 3d levels are introduced into the MgO band gap, which significantly reduce the fundamental gap as confirmed by optical absorption spectra.
References
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Journal ArticleDOI
Special quasirandom structures.
TL;DR: It is shown that it is possible to design special quasirandom structures'' (SQS) that mimic for small {ital N} the first few, physically most relevant radial correlation functions of a perfectly random structure far better than the standard technique does.
Journal ArticleDOI
Linear scaling electronic structure methods
TL;DR: In this paper, the physical decay properties of the density matrix were studied for both metals and insulators, and several strategies for constructing O(N) algorithms were presented and critically examined.
Journal ArticleDOI
The Alloy Theoretic Automated Toolkit: A User Guide
TL;DR: A concise user guide is presented outlining the steps required to obtain thermodynamic information from ab initio calculations of alloy thermodynamic properties from first-principles.
Journal ArticleDOI
Automating first-principles phase diagram calculations
A. van de Walle,Gerbrand Ceder +1 more
TL;DR: In this article, the authors present a statistical basis for the selection of both the interaction parameters to include in the cluster expansion and the structures to use to determine them, which is based on the concepts of cross-validation and variance minimization.
Journal ArticleDOI
Multicomponent multisublattice alloys, nonconfigurational entropy and other additions to the Alloy Theoretic Automated Toolkit
TL;DR: The Alloy Theoretic Automated Toolkit (ATATAT) as mentioned in this paper can handle multisublattice alloy systems, nonconfigurational sources of entropy (e.g. vibrational and electronic entropy), Special Quasirandom Structures (SQS) generation, tensorial cluster expansion construction and interfaces for multiple atomistic or ab initio codes.
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