The Fermi Gas Model Applied to the Thermal Electromotive Forces of Tin, Lead, and Indium

The absolute thermoelectric powers of tin, lead, and indium in the temperature range of 2−10°K are taken from data of Keesom and Matthijs. The temperature dependence of thermal e.m.f. is parabolic, as predicted for a Fermi gas. With an additional assumption regarding a mean free path parameter (i.e., d(logl)/dε≪1), the Fermi energies for tin, lead, and indium are calculated to be 5.72, 2.89, and 1.20 ev, respectively. Low temperature specific heat data then provide an estimate of the number of conduction electrons per atom. The latter values are 2.54, 2.39, and 0.50, respectively.