부산대학교 도서관

The electronic properties of three different oxides (ZnO, Sn[O.sub.2] and Si[O.sub.2]) are investigated within many-body perturbation theory in the [G.sup.0][W.sup.0] approximation. The frequency dependence of the dielectric function is either approximated using two different well-established plasmon-pole models (one of which enforces the fulfillment of the f-sum rule) or treated explicitly by means of the contour-deformation approach. Comparing these results, it is found that the plasmon-pole model enforcing the f-sum rule gives less accurate results for all three oxides. The calculated electronic properties are also compared with the available experimental data and previous ab initio results, focusing on the d state binding energies. The [G.sup.0][W.sup.0] approach leads to significantly improved band gaps with respect to calculations based on the density functional theory in the local density approximation.
1 Introduction While density functional theory (DFT) has proved to be successful in predicting the ground state properties of semiconductors and insulators, the corresponding predicted band gaps are systematically underestimated [...]