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 re...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）.展开更多
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 latti...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 ZnGa2Xa by fitting the Birch-Murnaghan＇s equation of state. The extended Cohen＇s empirical formula agrees well with our ab initio results.展开更多
A symmetry analysis and a simple dangling bond model are presented for the VZn^- in ZnGeP2, identifying a possible Jahn-Teller distortion mechanism which could naturally explain the localization of the defect wavefunc...A symmetry analysis and a simple dangling bond model are presented for the VZn^- in ZnGeP2, identifying a possible Jahn-Teller distortion mechanism which could naturally explain the localization of the defect wavefunction on two of the nearest-neighbouring P atoms, as deduced for the electron nuclear double resonance experiments.展开更多
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+1 种基金the Youth Scientific Research Foundation of Shanxi Province (Grant No. 2007021002)the Oversea Science Foundation of Shanxi Province
文摘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Supported by the National Natural Science Foundation of China under Grant No 10604040）, SRF for ROCS, SEM, the YSRF of Shanxi Province under Grant No 2007021002, and the Oversea Science Foundation of Shanxi.
文摘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 ZnGa2Xa by fitting the Birch-Murnaghan＇s equation of state. The extended Cohen＇s empirical formula agrees well with our ab initio results.
基金Supported by the National Natural Science Foundation of China Grant No 10604040, SRF for ROCS, SEM, the YSRF of Shanxi Grant No 2007021002, the Oversea Science Foundation of Shanxi, the Air Force Office of Scientific Research （USA） under Grant No F49620-03-1-0010
文摘A symmetry analysis and a simple dangling bond model are presented for the VZn^- in ZnGeP2, identifying a possible Jahn-Teller distortion mechanism which could naturally explain the localization of the defect wavefunction on two of the nearest-neighbouring P atoms, as deduced for the electron nuclear double resonance experiments.
