Energy Band Structure of Be–(C, Si, Ge, Sn)–N2 Crystals

Abstract

For the BeMN₂ (M = C, Si, Ge, Sn) crystals with the chalcopyrite lattice, model calculations of the electronic structure are performed, equilibrium parameters of the crystal lattice are obtained, band spectra, density of states, and charge distribution densities are calculated within the framework of the density functional theory using a B3LYP approximation. It is found that BeCN₂ is a pseudo-direct-gap crystal strongly compressed along the tetragonal axis (γ = 1.868), whereas BeSiN₂, BeGeN₂, and BeSnN₂ are stretched (γ > 2) direct-gap crystals with band gaps of 7.34, 5.71, 5.07, and 3.24 eV, respectively.