Band structure of SrFeAsF and CaFeAsF-the base phases of a new group of oxygen-free FeAs superconductors

The results of ab initio FLAPW-GGA calculations of the band structure of the recently synthesized four-component fluorine arsenides SrFeAsF and CaFeAsF, which are the base phases of a new group of oxygen-free FeAs superconductors, are presented. The energy bands, electron state density distributions, effective atomic charges, Fermi surface topology, low-temperature electronic specific heat, and molar Pauli paramagnetic susceptibility have been determined for SrFeAsF and CaFeAsF and are compared to similar data for oxyarsenide LaFeAsO, which is the base phase of the family of the recently discovered high-temperature (T (c) similar to 26-56 K) FeAs oxygen-containing superconductors.