Low-Temperature Specific Heat of an Extreme-Type-II Superconductor at High Magnetic Fields

Abstract

We present a detailed study of the quasiparticle contribution to the low-temperature specific heat of an extreme type-II superconductor at high magnetic fields. Within a T-matrix approximation for the self-energies in the mixed state of a homogeneous superconductor, the electronic specific heat is a linear function of temperature with a linear-$T$ coefficient ${\gamma }_s(H)$ being a nonlinear function of magnetic field $H$. In the range of magnetic fields $H\agt (0.15-0.2)H_{c2}$ where our theory is applicable, the calculated ${\gamma }_s(H)$ closely resembles the experimental data for the borocarbide superconductor YNi${}_2$B${}_2$C.

7 pages, 2 figures, to appear in Physical Review B