Electronic band structure and Fermi surface for new layered superconductor LaO0.5F0.5BiS2 in comparison with parent phase LaOBiS2 from first principles

By means of ab initio calculations, we have probed the peculiarities of the electronic band structure and Fermi surface for the recently discovered layered superconductor LaO_0.5F_0.5BiS₂ in comparison with the parent phase LaOBiS₂. The electronic factors promoting the transition of LaOBiS₂ upon fluorine doping to superconducting state: inter-layer charge transfer, the evolution of the Fermi surface, and the dependence of the near-Fermi densities of states on x for LaO_{1 ? x} F _x BiS₂ are evaluated and discussed in comparison with the available experiments.