Statistical physics of multicomponent alloys using KKRCPA
Abstract
We apply variational principles from statistical physics and the Landau theory of phase transitions to multicomponent alloys using the multiplescattering theory of KorringaKohnRostoker (KKR) and the coherent potential approximation (CPA). This theory is a multicomponent generalization of the S( ^{2}) theory of binary alloys developed by G. M. Stocks, J. B. Staunton, D. D. Johnson and others. It is highly relevant to the chemical phase stability of highentropy alloys as it predicts the kind and size of finitetemperature chemical fluctuations. In doing so it includes effects of rearranging charge and other electronics due to changing site occupancies. When chemical fluctuations grow without bound an absolute instability occurs and a secondorder orderdisorder phase transition may be inferred. The S( ^{2}) theory is predicated on the fluctuationdissipation theorem; thus we derive the linear response of the CPA medium to perturbations in sitedependent chemical potentials in great detail. The theory lends itself to a natural interpretation in terms of competing effects: entropy driving disorder and favorable pair interactions driving atomic ordering. Moreover, to further clarify interpretation we present results for representative ternary alloys CuAgAu, NiPdPt, RhPdAg, and CoNiCu within a frozen charge (or bandonly) approximation. These results include the socalled Onsager mean fieldmore »
 Authors:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division
 Univ. of Warwick, Coventry (United Kingdom). Dept. of Physics
 Publication Date:
 Research Org.:
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF)
 Sponsoring Org.:
 USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC22)
 OSTI Identifier:
 1328289
 Grant/Contract Number:
 AC0500OR22725
 Resource Type:
 Journal Article: Accepted Manuscript
 Journal Name:
 Physical Review B
 Additional Journal Information:
 Journal Volume: 93; Journal Issue: 5; Journal ID: ISSN 24699950
 Publisher:
 American Physical Society (APS)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 36 MATERIALS SCIENCE
Citation Formats
Khan, Suffian N., Staunton, Julie B., and Stocks, George Malcolm. Statistical physics of multicomponent alloys using KKRCPA. United States: N. p., 2016.
Web. doi:10.1103/PhysRevB.93.054206.
Khan, Suffian N., Staunton, Julie B., & Stocks, George Malcolm. Statistical physics of multicomponent alloys using KKRCPA. United States. doi:10.1103/PhysRevB.93.054206.
Khan, Suffian N., Staunton, Julie B., and Stocks, George Malcolm. 2016.
"Statistical physics of multicomponent alloys using KKRCPA". United States.
doi:10.1103/PhysRevB.93.054206. https://www.osti.gov/servlets/purl/1328289.
@article{osti_1328289,
title = {Statistical physics of multicomponent alloys using KKRCPA},
author = {Khan, Suffian N. and Staunton, Julie B. and Stocks, George Malcolm},
abstractNote = {We apply variational principles from statistical physics and the Landau theory of phase transitions to multicomponent alloys using the multiplescattering theory of KorringaKohnRostoker (KKR) and the coherent potential approximation (CPA). This theory is a multicomponent generalization of the S(2) theory of binary alloys developed by G. M. Stocks, J. B. Staunton, D. D. Johnson and others. It is highly relevant to the chemical phase stability of highentropy alloys as it predicts the kind and size of finitetemperature chemical fluctuations. In doing so it includes effects of rearranging charge and other electronics due to changing site occupancies. When chemical fluctuations grow without bound an absolute instability occurs and a secondorder orderdisorder phase transition may be inferred. The S(2) theory is predicated on the fluctuationdissipation theorem; thus we derive the linear response of the CPA medium to perturbations in sitedependent chemical potentials in great detail. The theory lends itself to a natural interpretation in terms of competing effects: entropy driving disorder and favorable pair interactions driving atomic ordering. Moreover, to further clarify interpretation we present results for representative ternary alloys CuAgAu, NiPdPt, RhPdAg, and CoNiCu within a frozen charge (or bandonly) approximation. These results include the socalled Onsager mean field correction that extends the temperature range for which the theory is valid.},
doi = {10.1103/PhysRevB.93.054206},
journal = {Physical Review B},
number = 5,
volume = 93,
place = {United States},
year = 2016,
month = 2
}
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