The electronic structure of novel BiS2-based layered superconductor

Abstract By means of the first-principles calculations, we studied the density of states, band structure and Fermi surface nesting of the recently discovered BiS 2 layered superconductor LaO 1− x F x BiS 2 . At x  = 0, the density of state and band structure of LaOBiS 2 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 LaO 1− x F x BiS 2 is not as strong as that of LaOFeAs.