The electronic structure of novel BiS2-based layered superconductor

By means of the first-principles calculations, we studied the density of states, band structure and Fermi surface nesting of the recently discovered BiS2 layered superconductor LaO1 xFxBiS2. At x = 0, the density of state and band structure of LaOBiS2 indicate the compound is a insulator with a band gap of 0.15 eV. It becomes metal with F-doping. At x = 0.5, there are four bands crossing the Fermi level. These four bands are mostly derived from the P-x and P-y orbitals of Bi atoms. Compared with the typical Fe-As based superconductor LaOFeAs, the Fermi surface nesting of LaO1-xFxBiS2 is not as strong as that of LaOFeAs. (C) 2013 Published by Elsevier B.V.