Quantum-mechanical modeling of the high-pressure state equations of ZnO and ZnS

Equations of state (EOS) for the high-pressure phases of ZnO and ZnS have been determined by carrying out ab initio perturbed-ion calculations. The results are used to examine different empirical EOS formalisms proposed for experimental P-V data. The generalized Vinet EOS is shown to be highly sensitive to the uncertainties in experimental data, thus providing a poor extrapolation for the properties at zero pressure. Contrarily, the modified Birch-Murnaghan EOS predicts zero-pressure properties that agree with ab initio calculations. © 1993 The American Physical Society

Theoretical study of the group-IV antisite acceptor defects in CdGeAs \u3c inf\u3e 2

Native and impurity antisite point defects in CdGeAs 2 are studied here using an embedded quantum cluster model based on density functional theory. The calculated geometric relaxations and spin densities of the antisite defects considered here show a clear and distinct difference in the nature of native (i.e. [Ge As]) and impurity (i.e. [C As] and [Si As]) antisite defects in CdGeAs 2. For the native antisite acceptor, the hole appears to be delocalized in contrast to impurity antisites where the hole is mainly localized at the acceptor site. © 2004 American Institute of Physics