Superconducting Interactions in Tin Telluride

Abstract

The range of superconductivity in tin telluride has been extended down to 4×${10}^{20}$ carriers per cc. Experimentally there is no indication of cutoff in superconductivity, although the data are not inconsistent with the theoretically indicated cutoff at 4×${10}^{19}$ carriers per ${\mathrm{cm}}^3$. By using a modified form of the Morel-Anderson theory in conjuction with a modified BCS equation due to McMillan, it is possible to fit the experimental data and to find the magnitude of the umklapp contribution to the attractive phonon interaction. The resulting values are approximately a factor of 10 smaller than the values predicted by the Morel-Anderson theory.