Bardeen-Kümmel-Jacobs-Tewordt Theory of a Vortex nearTc

Abstract

An expression for the free energy of a superconductor containing magnetic flux is derived for temperatures near $T_c$. To order $T_c-T$, the result is identical to that of Ginzburg-Landau as derived by Gor'kov. A term proportional to ${(T_c-T)}^{\frac{1}{2}}$ is shown to vanish in perturbation theory. The validity of the variational functions of Bardeen et al. is verified near $T_c$ where the critical value of $\kappa$ is almost identical to $\frac{1}{\sqrt{2}}$.