Quasi-Classical Calculation of the Mixed-State Thermal Conductivity in s-Wave and d-Wave Superconductors

TL;DR

This paper investigates how the superconducting gap structure influences the magnetic-field dependence of thermal conductivity in s-wave and d-wave superconductors using a quasi-classical approach that includes spatial variations.

Contribution

It introduces a quasi-classical calculation method that fully accounts for spatial variations of the Green's function, improving upon previous models.

Findings

Demonstrates differences in kappa_{xx}(B) between s-wave and d-wave superconductors.

Suggests kappa_{xx}(B) measurement as a probe for gap structure.

Provides a more accurate theoretical framework for thermal conductivity in superconductors.

Abstract

To see how superconducting gap structures affect the longitudinal component of mixed-state thermal conductivity kappa_{xx}(B), the magnetic-field dependences of kappa_{xx}(B) in s-wave and d-wave superconductors are investigated. Calculations are performed on the basis of the quasi-classical theory of superconductivity by fully taking account of the spatial variation of the normal Green's function, neglected in previous works, by the Brandt-Pesch-Tewordt approximation. On the basis of our result, we discuss the possibility of kappa_{xx}(B) measurement as a method of probing the gap structure.