Thermal Conductivity of Dilute Indium-Mercury Alloys

Abstract

The thermal conductivities of a series of polycrystalline specimens of indium containing 0.1 to 2.5 at.% mercury have been measured in the temperature range 1.4°-4.0°K. By using an extrapolation procedure, the amount of phonon conduction in the superconductive state was calculated and was found to be about one-half as large as the value calculated from the theory of Bardeen, Rickayzen, and Tewordt. From the ratio of the electronic thermal conductivity in the superconductive state to that in the normal state, the temperature and composition dependences of the Bardeen-Cooper-Schrieffer (BCS) energy gap were calculated. Small systematic deviations of the measured gaps from the predictions of the BCS theory were observed.