Adequacy of the local-spin-density approximation for Gd

Highly converged local-spin-density-approximation (LSDA) calculations for ferromagnetic hcp Gd have been perfomed using an extended general-potential linearized augmented-plane-wave method. These calculations are used to assess the adequacy of the LSDA for this material. It is found that, while the calculated ground-state properties are in better agreement with experiment than is the case for elements with open 4f shells, the LSDA does not provide a fully satisfactory description of this material. On the other hand, an analysis of the electronic structure suggests that a model with localized f electrons is unsuitable for Gd.