Ab-initio theory of semiconductor band structures: New developments and progress

摘要

We present most recent developments to calculate the electronicstates of semiconductors and insulators without taking into account experimental parameters. They are based on the solution of the quasiparticle equation starting with a reasonable zeroth order approximation for the electronic states and the GW approximation for the exchange–correlation selfenergy. Due to inclusion of screened exchange effects from the very beginning, self-consistency can be easily reached. The advantages with respect to a starting point based on single- particle eigenfunctions and eigenvalues of the groundstate density functional theory (DFT) are clearly shown for band gaps, positions of semicore d-bands, and densities of states. The progress is demonstrated for compounds containing first-row elements such as metal oxides and nitrides whose gaps are much too small or even negative within the conventional DFT.