Surface electronic structure of possible high-Tc surface superconductor WO3 based on the first-principles calculation

Abstract

Abstract The first-principles calculation is performed to investigate the surface electronic structure of WO3 in which high-Tc surface superconductivity up to Tc =120 K is observed when alkali metals are alightly doped. To take into account of the surface effect, we employ the tetragonal 14-layers slab model and find that a remarkable in-gap band with a narrow band width of 0.13 eV appears at about 0.6 eV below the conduction bands. Detailed analysis of the wave functions reveal that the in-gap band mainly consists of orbitals in the first and second layers on the surface. Therefore, the in-gap band is considered to play crucial role for the surface superconductivity in the slightly electron-doped WO3.