Theoretical study on the field dependence of the zero energy density of states in an anisotropic gap superconductors Original Research Article

Based on the quasi-classical theory, we calculate the zero energy density of states N(B) in the mixed state for a type II superconductor. N(B) is related to the sommerfeld coefficient γ(B), which gives us useful information for a superconducting gap. The linear portion in γ(B) relative to Bc2 and its slope in a low field reflect the gap anisotropy, so that we can distinguish the nodal gap and the anisotropic full gap, and estimate the magnitude of the gap anisotropy.