Electronic structure of non-centrosymmetric superconductors Re24(Nb;Ti)5 by ab initio calculations

Electronic structures of superconducting Re24Nb5 and Re24Ti5 have been calculated employing the full-potential local-orbital method within the density functional theory. The investigations were focused on the influence of the antisymmetric spin-orbit coupling on band structures and Fermi surfaces of these non-centrosymmetric systems. The predicted here density of states at the Fermi level for Re24Ti5 is abnormally low with respect to that deduced from previous heat capacity measurements. This discrepancy suggests an intermediate coupled superconducting state in Re24Ti5. The differences between electronic properties of both compounds could explain more robust superconductivity in the Nb-based material.