Density-functional theory modeling of bulk magnetism with spin-dependent pseudopotentials

The recently developed spin-dependent pseudopotentials markedly improve the description of the energetics of isolated transition metal atoms [S. C. Watson and E. A. Carter, Phys. Rev. B 58, R13 309 (1998)]. Spin-dependent pseudopotentials are obtained from a combination of spin-neutral and fully polarized atomic pseudopotentials, employing the self-consistent local spin polarization to adapt to different environments. Their use is extended to bulk materials in the current work, where we have implemented the spin-dependent pseudopotential formalism within a real-space density functional theory code. Calculations on bulk Fe, Co, and Ni yield lattice constants and bulk moduli within the accuracy expected of a method employing the local density approximation of density functional theory, except for an overestimated Fe bulk modulus. However, the magnetic moment is in dramatically better agreement with experiment and published all-electron calculations when the spin-dependent pseudopotentials are employed.