Assessment of quality and reliability of band structures from exact-exchange-only Kohn-Sham, hybrid, and GW methods

摘要

Band gaps for a large number of semiconductors obtained with the exact-exchange(EXX)-only Kohn-Sham method are compared to those from various generalized Kohn-Sham methods based on hybrid functionals and with experimental values. EXX band gaps are shown to be of superior quality than the band gaps from most of the considered hybrid methods, band gaps obtained with the hybrid functional HSE06 have a similar quality as EXX ones. The EXX method is found to yield d-electron binding energies that are clearly superior to those determined within the local density approximation and to be comparable to d-electron binding energies from GW approaches. EXX plane-wave pseudopotential calculations and EXX all-electron calculations are shown to yield very similar KS transition energies demonstrating that the plane-wave pseudopotential approach is well-suited for EXX methods. Previous discrepancies between pseudopotential and all-electron calculations, most likely, have to be attributed to technical problems in early all-electron EXX calculations.