Transport Properties and Fluctuations in Type II Superconductors Near $H_{c2}$

TL;DR

This paper investigates the flux-flow Hall effect and thermomagnetic transport near the upper critical field in extreme type-II superconductors, incorporating backflow effects and thermal fluctuations within a generalized time-dependent Ginzburg-Landau framework.

Contribution

It provides a comprehensive calculation of transport properties near Hc2, including backflow, fluctuations, and flux lattice elasticity, validating simplified mean-field approaches.

Findings

Hall conductivity agrees with mean-field calculations

Calculated thermomagnetic effects like Nernst and Ettingshausen effects

Incorporates thermal fluctuations and flux lattice elasticity effects

Abstract

We study the flux-flow Hall effect and thermomagnetic transport near the upper critical field \hctwo\ in extreme type-II superconductors starting from a suitable generalization of the time dependent Ginzburg-Landau equations. We explicitly incorporate the effects of backflow into the calculations of the local electric field and current, leading to a current which is properly divergenceless. The Hall conductivity calculated from this current agrees with other mean-field calculations which assume a uniform applied electric field (the Schmid-Caroli-Maki solution), thereby vindicating these simplified treatments. We then use these results to calculate the transverse thermomagnetic effects (the Ettingshausen and Nernst effects). The effects of thermal fluctuations and nonlocal elasticity of the flux lattice are incorporated using a method recently developed by Vecris and Pelcovits [G. Vecris and R. A. Pelcovits, Phys. Rev. B {\bf 44}, 2767 (1991)]. Our results, taken together with those of Vecris and Pelcovits, provide a rather complete description of the transport properties of the flux lattice state near \hctwo, at least within the framework of time dependent Ginzburg-Landau theory.