ELECTRONIC-STRUCTURE OF BECN2 - A PROPOSED NEARLY DIRECT WIDE-BAND-GAP SEMICONDUCTOR

The electronic band structure of a hypothetical compound BeCN2 in the chalcopyrite structure has been calculated using the linear-muffin-tin-orbital method and the local-density approximation (LDA) for exchange and correlation. The calculations predict a lattice constant of 3.67 angstrom, a bulk modulus of 315 GPa, and a cohesive energy of 6.1 eV/atom. The band gap is found to be nearly direct at the GAMMA-point. The conduction-band minimum, which occurs at k = 2-pi/a(0.89, 0, 0), is only 0.03 eV below the lowest conduction-band state at the GAMMA-point. The minimum band gap is estimated to be 5.7 eV including corrections beyond the LDA. The band-gap hydrostatic deformation potential is calculated to be 0.4 eV.