Fermi-surface topology and pairing symmetry in BiS2-based layered superconductors

[摘要] In order to clarify superconducting properties of BiS2-based layered superconductors LaO1-xFxBiS2, we evaluate the superconducting transition temperature T-c and analyze the gap function in a weak-coupling limit on the basis of the two-dimensional two-orbital Hubbard model. It is found that Tc becomes maximum at x=0.6 in the present calculations. For x < 0.45, we obtain the d-wave gap of which line nodes do not cross the pocket-like Fermi-surface curves with the centers at X and Y points. On the other hand, for x > 0.45, the extended s-wave gap is found for a couple of large Fermi-surface curves with the centers at M and X points. The variation of the Fermi-surface topology plays a key role for the gap symmetry in BiS2-based superconductors. (C) 2015 Elsevier B.V. All rights reserved.

[发布日期] 2016-02-15

[效力级别]  Proceedings Paper

[关键词] BiS2;Fermi surface;Superconductivity;Extended s-wave;d-wave