摘要
We have performed a first-principles investigation for the family of compounds ZnGa2X4 （X = S, Se, Te）. The properties of two possible structures, defect chalcopyrite and defect famatinite are both calculated. We reveal that ZnGa2S4 and ZnGa2Se4 have direct band gaps, while ZnGa2Te4 has an indirect band gap. The local density approximation band gaps are found to be very different in two structures, while the lattice parameters and bulk moduli are similar. We extend Cohen＇s empirical formula for zinc-blende compounds to this family of compounds. The pressure coefficients are calculated and metallization pressures are discussed. We find that agi remains fairly constant when thegroup-V/element X is varied in ZnGa2X4（Ⅱ-Ⅲ2-Ⅵ4）.
We have performed a first-principles investigation for the family of compounds ZnGa2X4 （X = S, Se, Te）. The properties of two possible structures, defect chalcopyrite and defect famatinite are both calculated. We reveal that ZnGa2S4 and ZnGa2Se4 have direct band gaps, while ZnGa2Te4 has an indirect band gap. The local density approximation band gaps are found to be very different in two structures, while the lattice parameters and bulk moduli are similar. We extend Cohen＇s empirical formula for zinc-blende compounds to this family of compounds. The pressure coefficients are calculated and metallization pressures are discussed. We find that agi remains fairly constant when thegroup-V/element X is varied in ZnGa2X4（Ⅱ-Ⅲ2-Ⅵ4）.
基金
Project supported by the National Natural Science Foundation of China (Grant No. 10604040)
Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Mininstry
the Youth Scientific Research Foundation of Shanxi Province (Grant No. 2007021002)
the Oversea Science Foundation of Shanxi Province
