LOCALIZED ORBITALS AND SINGLE-ELECTRON SPECTRUM IN SELF-INTERACTION-CORRECTED DENSITY-FUNCTIONAL THEORY

The density-functional theory for the Hubbard model has been studied within the local-density approximation and its self-interaction-corrected (SIC) version with special reference to a single-particle excitation spectrum. A powerful algorithm based on an idea of simulated annealing has been proposed and applied to obtaining the localized orbitals minimizing the SIC total energy, where off-diagonal Lagrange multipliers are fully taken into account to guarantee orthogonality of the SIC orbitals. The possible prescriptions for calculating a reliable band structure for a half-filled insulating case have been discussed both for the valence and conduction bands. © 1990 The American Physical Society.