Electrical resistivity of potassium at low temperatures

Abstract

The low-temperature electrical resistivity of potassium is calculated and compared with the recent, highly accurate measurements in the range 2-20 °K. Excellent agreement with experiment is obtained. It is found that explicity including phonon drag accounts precisely for the exponential temperature dependence observed for the resistivity below 4 °K. We show how to determine the screened electron-ion interaction matrix elements, crucial for obtaining quantitative agreement with experiment for a resistivity calculation in the low-temperature regime. A discussion is given showing in detail how the present calculated results for potassium are in quantitative agreement with the general theory of the low-temperature resistivity of the alkali metals.