Thermal conductivity of superconducting Bi2Sr2CaCu2O8 and YBa2Cu3O7−y

Abstract

Allen et al. [Phys. Rev. B 49, 9073 (1994)] have considered the thermal conductivity in a metallic superconductor Bi2Sr2CaCu2O8 and an insulating parent Bi2Sr2YCu2O8. Allen et al. have stressed that the theory of the thermal conductivity of high-Tc superconductors should account for the fact that the peak observed in κab(T) should be more pronounced in YBa2Cu3O7−δ than in Bi2Sr2CaCu2O8. We have performed calculations of the electronic component of the thermal conductivity of such high-Tc compounds using a variational method. We have considered elastic scattering of electrons by impurities as well as elastic and inelastic scattering of electrons by acoustic phonons. We have used a two-dimensional density of states and an anisotropic electron spectrum with a Josephson-like coupling J between the superconducting planes to better describe 2D-like systems. We show the J dependence of the thermal conductivity and conclude that the different behavior of the thermal conductivity in YBa2Cu3O7−δ and in Bi2Sr2CaCu2O8, i.e., the less pronounced peak in κab in the latter system, should be due mainly to the more pronounced layered structure and is indeed of electronic origin.

Source-reported materials — not catalogue approval

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