Mean-field approximations for the electronic states in disordered alloys

Abstract

Mean-field approximations are used to find approximate solutions to the one-electron equations for the electronic states in disordered alloys because ordinary band-theory approaches are not applicable. The first mean-field approximation, the coherent potential approximation, does not treat Coulomb effects correctly. This has been improved by changing the way the mean-field approximation is implemented. It may be that this experience with mean-field approximations will be useful to the combination of many-body theory and mean-field theory that has produced the dynamical coherent potential approximation and dynamical mean field theory for treating strongly correlated electron systems.

Acknowledgements

This work was supported in part by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, US Department of Energy, and by the Laboratory Directed Research and Development program of Oak Ridge National Laboratory (ORNL), under Contract No. DE-AC05-00OR22725 with UT-Battelle. Much of the research was done during visits to the Metals and Ceramics Division at ORNL that were made possible by SURA Summer Cooperative Research Grants in Materials Science at ORNL that are administered by the Southeastern Universities Research Association (SURA). We thank Dr. Y. Wang for his valuable advice. Computations were performed on the Cray T3E at the National Energy Research Scientific Computing Center, the Cray T3E at the Pittsburgh Supercomputing Center, and on the Boca Cluster at the Florida Atlantic University.