Reformulation of the nonlocal coherent-potential approximation: a unique reciprocal-space theory of disorder
- ORNL
The nonlocal coherent-potential approximation (NLCPA) has recently been introduced for describing short-range correlations in disordered systems, for example short-range ordering e ects in alloys. As a generalisation of the widely-used coherent-potential approximation (CPA), the NLCPA determines an e ective medium via the self-consistent embedding of a cluster with periodic Bornvon Karman boundary conditions imposed. Whilst this approach has the advantageous property of preserving the single-site translational invariance of the underlying lattice, it has recently been shown to yield spurious and non-unique results below some critical cluster size. In this paper we reformulate the NLCPA as a unique and systematic theory and show that the previous formalism is a specific limiting case of the new formulation. We explicitly demonstrate the theory for a one-dimensional tight-binding model in order to compare with exact numerical results.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 946762
- Journal Information:
- Physical Review B, Vol. 78, Issue 11
- Country of Publication:
- United States
- Language:
- English
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