By means of first-principle FLAPW-GGA calculations, we have investigated the
electronic properties of the newly discovered layered quaternary systems
SrFeAsF and CaFeAsF as parent phases for a new group of oxygen-free FeAs
superconductors. The electronic bands, density of states, Fermi surfaces,
atomic charges, together with Sommerfeld coefficients and molar Pauli
paramagnetic susceptibility have been evaluated and discussed in comparison
with oxyarsenide LaFeAsO - a parent phase for a new class of high-temperature
(Tc about 26-56K) oxygen-containing FeAs superconductors. Similarity of our
data for SrFeAsF and CaFeAsF with the band structure of oxygen-containing FeAs
superconducting materials may be considered as theoretical background
specifying the possibility of superconductivity in these oxygen-free systems.Comment: 12 pages, 3 figure