Investigate the effect of anisotropic order parameter on the specific heat of anisotropic two-band superconductors

The effect of anisotropic order parameter on the specific heat of anisotropic two-band superconductors in BCS weak-coupling limit is investigated. An analytical specific heat jump and the numerical specific heat are shown by using anisotropic order parameters, and the electron-phonon interaction and non-electron-phonon interaction. The two models of anisotropic order parameters are used for numerical calculation that we find little effect on the numerical results. The specific heat jump of MgB2, Lu2Fe3Si5 and Nb3Sn superconductors can fit well with both of them. By comparing the experimental data with overall range of temperature, the best fit is Nb3Sn, MgB2, and Lu2Fe3Si5 superconductors.