Superconductivity in Two-Band Model

Superconductivity in two-band models involving non s·wave pairing is investigated. We con-sider the following case: one band has s-wave pairing interaction and the other has non s-wave pairing interaction, and only s-wave Cooper pairs can be transferred between bands. Possible appearance of non s-wave superconducting order parameter in an s·wave superconducting state and its onset temperature are discussed. The non s·wave order parameter is suppressed by s-wave supercon-ductivity, and cannot appear unless the non s·wave pairing interaction is stronger than critical value. We also consider the appearance of s-wave superconducting order parameter in a non s-wave superconducting state. In this case, the s-wave order parameter can always appear on lowering temperature. Temperature dependence of the order parameters and the specific heat are shown in a simple case