A self-consistent energy-band study in CuCl

A self-consistent study of the energy bands in CuCl has been performed as a function of the lattice constant using the Hartree-Fock method. Correlation corrections are included. The principal results are that the upper valence band is formed mostly from the Cu 3d level and that for a normal lattice constant there is no indirect band gap; the direct band gap is calculated to be 4.0 eV and is at the Gamma point. With a decreasing lattice constant, a weak indirect gap developes between the valence band maximum at Gamma and a conduction band minimum at X. With a reduction of about 5% in the lattice constant, the indirect gap width has a value of about 2.0 eV. The results are discussed in the light of recent experimental data on CuCl.