Effect of La Doping on the Electronic Structure of BiS2-Based Superconductor Sr_{1-x}LaxFBiS2
Abstract
By means of first-principles calculations, we have systematically studied the La doping effect for the recently discovered layered BiS2-based superconductor Sr_{1-x}LaxFBiS2 (x = 0-0.7). For the electronic structure, we obtained the band structure, density of states (DOS), and Fermi surface (FS) at different doping levels. The parent compound SrFBiS2 is a semiconductor with a gap of 0.88 eV. The substitution of Sr by La dopes electrons and turns the system from a semiconductor to a metal. The band structure and the FS topology also change obviously with the increasing of doping level. Good FS nesting at the wave vector (π π 0 ) has been found at certain doping levels, suggesting a proximity to charge-density-wave instability. Particularly, the doping dependence of DOS at the Fermi level resembles the available experimental variation of Tc as the function of x, indicating that it may be a conventional phonon-mediated superconductor. This was further proved by electron-phonon coupling calculation. Therefore, similar to LaO_{1-x}FxBiS2, our results suggest another example of superconductor derived from doped semiconductor.
- Publication:
-
Journal of Low Temperature Physics
- Pub Date:
- December 2015
- DOI:
- 10.1007/s10909-015-1341-7
- Bibcode:
- 2015JLTP..181..242W