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Title: First-principles study of tantalum-arsenic binary compounds

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Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Solid-State Solar-Thermal Energy Conversion Center (S3TEC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
DOE Contract Number:
SC0001299; FG02-09ER46577
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 121; Journal Issue: 1; Related Information: S3TEC partners with Massachusetts Institute of Technology (lead); Boston College; Oak Ridge National Laboratory; Rensselaer Polytechnic Institute
Country of Publication:
United States
solar (photovoltaic), solar (thermal), solid state lighting, phonons, thermal conductivity, thermoelectric, defects, mechanical behavior, charge transport, spin dynamics, materials and chemistry by design, optics, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing)

Citation Formats

Sun, Jifeng, and Singh, David J. First-principles study of tantalum-arsenic binary compounds. United States: N. p., 2017. Web. doi:10.1063/1.4973273.
Sun, Jifeng, & Singh, David J. First-principles study of tantalum-arsenic binary compounds. United States. doi:10.1063/1.4973273.
Sun, Jifeng, and Singh, David J. Sat . "First-principles study of tantalum-arsenic binary compounds". United States. doi:10.1063/1.4973273.
title = {First-principles study of tantalum-arsenic binary compounds},
author = {Sun, Jifeng and Singh, David J.},
abstractNote = {},
doi = {10.1063/1.4973273},
journal = {Journal of Applied Physics},
number = 1,
volume = 121,
place = {United States},
year = {Sat Jan 07 00:00:00 EST 2017},
month = {Sat Jan 07 00:00:00 EST 2017}
  • The generation of Frenkel defects (a self-interstitial and a vacancy) in heavily As doped Si is investigated theoretically based on first-principles total energy calculations. We find that it is much easier to generate a self-interstitial and a vacancy close to substitutional As atoms than in pure Si, due to the lower energy cost. The As atom binds strongly with the vacancy, but does not bind with Si self-interstitial and other As atoms. We have considered several different reactions such as Si{sub 5}{yields}Si{sub 4}V+I, AsSi{sub 4}{yields}AsSi{sub 3}V+I, As{sub 2}Si{sub 3}{yields}As{sub 2}Si{sub 2}V+I, As{sub 3}Si{sub 2}{yields}As{sub 3}SiV+I, and As{sub 4}Si{yields}As{sub 4}V+I. Themore » theoretical results are in good agreement with experimental observations. (c) 2000 American Institute of Physics.« less
  • Here, we apply density-functional theory calculations to predict dopant modulation of electrical conductivity (σ o) for seven dopants (C, Si, Ge, H, F, N, and B) sampled at 18 quantum molecular dynamics configurations of five independent insertion sites into two (high/low) baseline references of σo in amorphous Ta 2O 5, where each reference contains a single, neutral O vacancy center (V O 0). From this statistical population (n = 1260), we analyze defect levels, physical structure, and valence charge distributions to characterize nanoscale modification of the atomistic structure in local dopant neighborhoods. C is the most effective dopant at loweringmore » Ta 2O x σ o, while also exhibiting an amphoteric doping behavior by either donating or accepting charge depending on the host oxide matrix. Both B and F robustly increase Ta 2O x σ o, although F does so through elimination of Ta high charge outliers, while B insertion conversely creates high charge O outliers through favorable BO 3 group formation, especially in the low σ o reference. While N applications to dope and passivate oxides are prevalent, we also found that N exacerbates the stochasticity of σ o we sought to mitigate; sensitivity to the N insertion site and some propensity to form N-O bond chemistries appear responsible. Finally, we use direct first-principles predictions of σ o to explore feasible Ta 2O 5 dopants to engineer improved oxides with lower variance and greater repeatability to advance the manufacturability of resistive memory technologies.« less
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  • Two types of global space-group optimization (GSGO) problems can be recognized in binary metallic alloys A{sub q}B{sub 1-q}: (1) configuration search problems, where the underlying crystal lattice is known and the aim is finding the most favorable decoration of the lattice by A and B atoms and (2) lattice-type search problems, where neither the lattice type nor the decorations are given and the aim is finding energetically favorable lattice vectors and atomic occupations. Here, we address the second, lattice-type search problem in binary A{sub q}B{sub 1-q} metallic alloys, where the constituent solids A and B have different lattice types. Wemore » tackle this GSGO problem using an evolutionary algorithm, where a set of crystal structures with randomly selected lattice vectors and site occupations is evolved through a sequence of generations in which a given number of structures of highest LDA energy are replaced by new ones obtained by the generational operations of mutation or mating. Each new structure is locally relaxed to the nearest total-energy minimum by using the ab initio atomic forces and stresses. We applied this first-principles evolutionary GSGO scheme to metallic alloy systems where the nature of the intermediate A-B compounds is difficult to guess either because pure A and pure B have different lattice types and the (1) intermediate compound has the structure of one end-point (Al{sub 3}Sc, AlSc{sub 3}, CdPt{sub 3}), or (2) none of them (CuPd, AlSc), or (3) when the intermediate compound has lattice sites belonging simultaneously to a few types (fcc, bcc) (PdTi{sub 3}). The method found the correct structures, L1{sub 2} type for Al{sub 3}Sc, D0{sub 19} type for AlSc3, 'CdPt{sub 3}' type for CdPt{sub 3}, B2 type for CuPd and AlSc, and A15 type for PdTi{sub 3}. However, in such stochastic methods, success is not guaranteed, since many independently started evolutionary sequences produce at the end different final structures: one has to select the lowest-energy result from a set of such independently started sequences. Interestingly, we also predict a hitherto unknown (P 2/m) structure of the hard compound IrN{sub 2} with energy lower than all previous predictions.« less