Quasiparticle self-consistent GW method applied to localized 4f electron systems

Rare-earth pnictides possess unique electronic and magnetic properties that make them interesting for both fundamental and practical reasons. We apply the quasiparticle self-consistent GW (QSGW) method to the rare-earth metals Gd and Er and to the rare-earth monopnictides GdN, EuN, YbN, GdAs, and ErAs. QSGW is unique in that it automatically takes into account both spd and f electrons in a single, unified framework without any materials-dependent parameters or special treatment of the f electrons. It enables us to examine approximations behind the standard local density approximation+U and self-interaction corrected approaches. QSGW reproduces the experimental occupied 4f levels well, though the unoccupied levels are a little overestimated. Properties of the Fermi surface responsible for electronic properties-governed by the spd electrons-are in good agreement with available experimental data. GdN is predicted to be very near a critical point of a metal-insulator transition.