Inclusion of charge correlations in calculations of the energetics and electronic structure for random substitutional alloys
- Division 8341, Sandia National Laboratories, Livermore, California 94551-0969 (United States)
- Department of Physics, University of Cincinnati, Cincinnati, Ohio 45221-0011 (United States)
Currently, the coherent-potential approximation (CPA) implemented via the multiple-scattering theory of Korringa, Kohn, and Rostoker (KKR) gives the best first-principles description of the electronic structure for random substitutional alloys. However, the total energy has an important component of electrostatic energy missing, namely, that arising from the correlation of charges with varying atomic environments. We develop a charge-correlated'' CPA method (cc-CPA) which includes (some) local environmental charge correlations within the KKR-CPA method. We investigate the cc-CPA energetics for several alloys and show that the formation energies are in better agreement with experimental results. These calculations show that the excess charge on a species is almost completely screened by the first-neighbor shell. We then derive a simplified scheme to include the vast majority of the omitted electrostatic energy from charge correlations which requires only a species-dependent shift of the potentials within the original KKR-CPA method. We also discuss the ramifications on the electronic structure.
- OSTI ID:
- 5968015
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Vol. 48:16; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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