Electronic structure of carbosulfide superconductors

Abstract

We present electronic band structure calculations and x-ray emission and photoelectron measurements of the recently discovered van der Waals-type layered superconductors Nb2S2C and Cu2/3Nb2S2C. Good agreement between our local partial density-of-states calculations and our experimental x-ray emission measurements of the constituents as well as between calculated and experimental E(k) dispersion curves is found for Nb2S2C. For Cu2/3Nb2S2C, we observe a strong interaction between Cu 3d and S 3s3p states that is responsible for shifting the S 3s3p states toward to the bottom of the valence band.