Local Spin-Density Calculation for Iron: Effect of Spin Interpolation on Ground State Properties.

摘要

Scalar relativistic self consistent linearized muffin-tin orbital (LMTO) calculations for bcc and fcc Fe have been performed with several different local approximations to the exchange and correlation energy density and potential. Overall, in contrast to the conclusions of previous studies. The local spin density approximation (LSDA) to exchange and correlation can provide an adequate description of bulk Fe, provided a proper parameterization of the correlation energy density and potential of the homogeneous electron gas over both spin and density is used. Lattice constants, found from the position of the minimum of the total energy as a function of Wigner-Seitz radius, agree to within 1-2% of the experimental lattice constants for all forms used for the local correlation. The best agreement, however, was obtained using a local correlation potential derived from the Vosko-Wilk-Nusair form for the spin dependence of the correlation energy density. The calculation performed with this correlation potential was also the only calculation to correctly predict a bcc ferromagnetic ground state. All the calculations gave satisfactory values for the magnetic moment, though the experimental bulk modulus was overestimated by more than 30%, a feature in agreement with most previously published calculations. (jhd)