Bulk Modulus and Electronic Band Structure of ZnGa ₂ <i>X</i> ₄ ( <i>X</i> = S,Se): a First-Principles Study

Abstract

First-principles local density functional calculations are presented for the compounds ZnGa2X4 (X = S,Se). We investigate the bulk moduli and electronic band structures in a defect chalcopyrite structure. The lattice constants and internal parameters are optimized. The electronic structures are analysed with the help of total and partial density of states. The relation between the cohesive energy and the unit cell volume is obtained by fully relaxed structures. We derive the bulk modulus of ZnGa2X4 by fitting the Birch–Murnaghan's equation of state. The extended Cohen's empirical formula agrees well with our ab initio results.