Self-interaction-correction theory for density functional calculations of electronic energy bands for the lithium chloride crystal

Recently a scheme has been developed to correct for the incomplete cancellation of the self-Coulomb interaction by the self-exchange term inherent in the local-spin-density (LDS) approximation to the Hartree-Fock theory. A calculation of the electronic energy band structure of the lithium chloride crystal is performed using the LSD theory with the self-interaction correction (SIC). The method of linear combinations of atomic orbitals is employed to solve the Hamiltonian self-consistently with four different versions of the exchange-correlation functional. The calculated band gap is in good agreement with the experimental value but becomes much smaller if the SIC is omitted. The binding energy of the centroid of the valence band obtained from the SIC-LSD calculation is slightly larger than the observed value. The density of states of the lower part of the conduction band is compared with photoemission data. The nature of the SIC potential is discussed and a simplified scheme for incorporating the SIC in the density functional theory is presented.