The black phosphorus band structure calculation with a semi-empirical crystal orbital approach

Abstract The energy band structure of black phosphorus is calculated with the Hartree—Fock self-consistent-field crystal-orbital method using the CNDO/2 approximation. The band gap is found at the point in the first Brillouin zone that corresponds to the direction perpendicular to the phosphorus layer. The lowest-order correction of Koopmans' theorem is estimated with the diagonal approximation of the k space-extended one-particle Green function method. As a result, the drastic reduction of band gap from 7.85 to 2.20 eV is found.