Thermal Conductivity of SnTe between 100° and 500°K

Abstract

The thermal conductivity, electrical conductivity, and Seebeck coefficient of several specimens of SnTe have been measured between 100° and 500°K. The thermal conductivity is weakly dependent on both temperature and hole concentration. The total thermal conductivity is separated into an electronic and a lattice thermal conductivity. Because of the large concentrations of Sn vacancies in the samples, the phonons are scattered both by three‐phonon umklapp processes and by the Sn vacancies; this results in a lattice thermal conductivity that varies with temperature more like T^−½ rather than T⁻¹. The Lorenz number relating the electrical conductivity and the electronic thermal conductivity is an unusual function of hole concentration. The Lorenz number is larger than the Sommerfeld value L₀, varies with hole concentration p, and has a maximum value of about 1.3 L₀ at p=2×10²⁰ cm⁻³. This is consistent with the variation of the electrical conductivity and the Seebeck coefficient with hole concentration.