SELF-INTERACTION-CORRECTED DENSITY-FUNCTIONAL FORMALISM .2. BAND-STRUCTURE OF THE HUBBARD-PEIERLS MODEL

A self-consistent scheme is presented to predict excitations energies of highly correlated many-electron systems within the self-interaction-corrected local-spin-density approximation. It is based on the minimization of the self-interaction-free total energy. This method yields a global picture of the excitation energies in the form of an effective wave-vector-resolved band structure for occupied and empty eigenstates which are automatically orthogonal to each other. The theory has been tested for the Hubbard-Peierls model in one and two dimensions. The electron removal energies and fundamental energy gaps are found to be substantially more accurate than in the standard local-density theory.