M. Battocletti et al., INFLUENCE OF GRADIENT CORRECTIONS TO THE LOCAL-DENSITY-APPROXIMATION ON THE CALCULATION OF HYPERFINE FIELDS IN FERROMAGNETIC FE, CO, AND NI, Physical review. B, Condensed matter, 53(15), 1996, pp. 9776-9783
Results of hyperfine field calculations for ferromagnetic bcc Fe, fee
Co, and fee Ni based on the scalar relativistic Korringa-Kohn-Rostoker
Green's-function formalism and using various parametrizations for the
exchange-correlation energy and the corresponding potential are prese
nted. Especially the influence of gradient corrections on the electron
ic structure in the nucleus-near region is investigated. The resulting
exchange potentials using these generalized gradient approximations (
GGA) lead to the necessity to introduce a finite nucleus model instead
of a point nucleus. This procedure removes the divergencies inherent
in the general expression for the exchange potential of the GGA's as t
he radius r approaches 0. However, it has only little impact on the hy
perfine fields, although pronounced changes in the charge densities in
the nucleus-near region are observed. While the hyperfine fields calc
ulated with one of the GGA's are in general higher than those for the
local parametrizations, they are still 16-24% too low compared with ex
periment.