Interplay of order parameters in an \(s+d\) two-band superconducting model

We extended the \(s+s\) two-band superconducting model proposed by Suhl et al. and Moskalenko to the \(s+d\) case and investigated the interplay between different superconducting order parameters. Unlike the \(s+s\) model in which the two s-wave order parameters are mutuality enhanced and disappear at the same transition temperature, we found that the d-wave order parameter is apparently suppressed by the s-wave pairing in the \(s+d\) two-band model. More over, the s- and d-wave order parameters usually disappear at different temperatures, implying that two separated phase transitions occur. The two phase transitions can be further confirmed by calculating the specific heat.