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

Abstract

To see how superconducting gap structures affect the longitudinal component of mixed-state thermal conductivity κ_xx(B), the magnetic-field dependences of κ_xx(B) in s- 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 κ_xx(B) measurement as a method of probing the gap structure.