We present a method for calculating the self-energy in the GW approximation
that can be applied to systems containing 3d and 4f electrons. The method
is applied to NiO and a gap of approximately 5.5 eV is obtained, which
is in reasonable agreement with the experimental value of 4.0 eV. The local
density O p band is also improved. The high binding energy satellite at
8 eV, however, is not obtained and there is no substantial increase of
O p character at the top of the valence band compared to the local density
result. Based on our results, we discuss to which extent the GW approximation
is capable of describing highly correlated systems such as NiO.
Physical Review Letters, 74 3221-4, 1995.
Max-Planck Institut für Festkörperforschung;
Postfach 80 06 65 D-70506 Stuttgart
