Electronic specific heat of anisotropic superconductors and its doping dependence

The specific heat of electrons in p- and d-symmetry superconducting states (CS) is comparatively studied within the BCS framework. This study is performed on a square lattice described by a generalized Hubbard model, in which correlated-hopping interactions are included in addition to the repulsive Coulomb ones. The temperature dependences of CS show a power law behavior, instead of the exponential behavior found in the s channel, and for a given gap amplitude the number of nodes in the gap enhances CS in the low temperature regime. Moreover, the normalized discontinuity of CS at the critical temperature (Tc) is smaller than the BCS analytical result of 1.43 for a wide range of electron densities. Finally, the results show that the single-particle van Hove singularity determines the location of the maximum gap, and then the position of the maximum discontinuity of the specific heat at Tc