Model supercell local-density calculations of the 3d excitation spectra in NiO

The local-density supercell impurity approach is used to calculate the excitation spectra due to the emission and absorption of a 3d electron in the Mott insulator NiO. Good agreement is found with both photoemission (PES) and inverse photoemission [bremsstrahlung isochromat spectroscopy (BIS)] data. In particular, a BIS excitation gap of 4.1 eV is found compared to 4.3 eV experimentally. The predicted values for the screened Coulomb interaction U is 7.9 eV. These results indicate that there is no conflict between the band picture of Terakura et al. for the ground-state properties of NiO and the excited-state properties derived from PES and BIS by Sawatzky and Allen and by McKay and Henrich.