Effect of asymmetric spin–orbit coupling on the electronic structure properties of noncentrosymmetric superconductor

Abstract

We report a theoretical investigation of the electronic structure properties of weakly correlated electronic noncentrosymmetric superconductor ( K). The first-principle calculations have been performed using the full potential linearised-muffin-thin-orbital method and including both scalar relativistic and fully relativistic (FR) treatments. We detect distinct differences between the data obtained from the two applied approaches. In particular, the bands along the , and separate and Fermi surfaces become highly anisotropic in FR calculations. The observed differences are ascribed to a strong effect of the asymmetric spin–orbit coupling with a splitting energy of order of –100 meV. Furthermore, we unveil that the valence bands originating from the Fe-3d orbitals essentially compose peak-structured profile in density of states (DOS) with a sharp peak situated at 0.65 eV below . The latter feature reflects the presence of a Van Hove type singularity. The main contribution to DOS at the Fermi level , however, comes equally from the Th-6d and Fe-3d electronic orbitals. The calculated value = 16.7 eV/f.u results in theoretical Sommerfeld coefficient = 39.31 mJ/mol K and electron–phonon coupling parameter = 0.34. The theoretical electronic structure properties of are discussed in comparison with those of other noncentrosymmetric superconductors.