Correlation energy functionals for ab initio calculations: Application to transition metals.

Abstract

The method for including strong correlation effects in self-consistent electronic structure calculations in solids is presented. On the basis of the mean-field-type (Gutzwiller-type) approximation the correlation energy functional is obtained, which depends on the partial electron density. In turn, the variation of this functional yields the nonlocal effective potential. Two possible variational procedures are tested: variation of the functional over occupation numbers only and over both occupation numbers and linear-muffin-tin-orbital--atomic-sphere-approximation (LMTO-ASA) wave function. The LMTO-ASA calculations for a number of 3d and 4d transition metals are carried out. The results are compared with those for density-functional calculations. Quantitative estimates of the correlation renormalization factor for the bandwidth ``dynamical'' narrowing in these metals are presented.