基于BiS2的超导体配对对称性

he possible pairing symmetries for BiS2-based superconductors is investigated by using a minimal two-orbital model with onsite and nearest-neighbor intraorbital attractions V0 and V1, respectively. By using the mean-field approximation and solving the self-consistent equations, the phase diagram of the pairing symmetry is obtained. It is shown that the model allows three possible pairing symmetries, depending on the values of $V_{0}$ and $V_{1}$: the isotopic $s-$wave pairing [$Delta_{mathbf{k}}=Delta_{s}$], the anisotropic $s-$wave pairing [$Delta_{mathbf{k}}=Delta_{s}+ rac{Delta_{xs}}{2}(cos k_{x}+cos k_{y})$] and the $d-$wave pairing [$Delta_{mathbf{k}}= rac{Delta_{d}}{2}(cos k_{x}-cos k_{y})$]. Furthermore the density of states for these pairing symmetries exhibit different behaviors which can be used to distinguish them.