The temperature-dependent electrical resistivities of the alkali metals

This review contains a comprehensive examination of all modern measurements and calculations of the temperature-dependent electrical resistivity $\rho \mathrm{}\left(T\right)\mathrm{}$ for the alkali metals—and especially potassium (K)—from their melting points down to below 0.1 K. The simplicity of the electronic structures of these metals makes them unique for testing our fundamental understanding of $\rho \mathrm{}\left(T\right)\mathrm{}$. At all temperatures down to a few K, $\rho \mathrm{}\left(T\right)\mathrm{}$ is dominated by its electron-phonon scattering component, ${\rho }_{\mathrm{ep}}\mathrm{}\left(T\right)\mathrm{}$. Current quantitative understanding of ${\rho }_{\mathrm{ep}}\mathrm{}\left(T\right)\mathrm{}$ in the alkali metals is examined in detail, including effects of phonon drag at temperatures below ≃ 10 K. In the vicinity of 1 K, $\rho \mathrm{}\left(T\right)\mathrm{}$ in pure, unperturbed, bulk alkali metals is predicted to be dominated by electron-electron scattering. ${\rho }_{\mathrm{ee}}\mathrm{}\left(T\right)=A_{\mathrm{ee}}{T}^2$. In disagreement with previous reviews, the authors argue that $A_{\mathrm{ee}}$ is nearly constant for each alkali metal and—at least for K—also in quantitative agreement with calculation. Below 1 K, alloys based on K and lithium display both previously predicted and completely unexpected effects. Perturbations such as deformation and thinning of K wires induce unusual and interesting behaviors. An unexpected Kondo-like effect appears when K contacts polyethylene. Charge-density-wave-based predictions of contributions to $\rho \mathrm{}\left(T\right)\mathrm{}$ in the alkali metals are also considered. Three appendices examine (a) what is involved in a realistic calculation of $\rho \mathrm{}\left(T\right)\mathrm{}$; (b) the experimental problems encountered in high-precision measurements of $\rho \mathrm{}\left(T\right)\mathrm{}$ at low temperatures and how they are solved; and (c) the most recent experimental data concerning charge-density waves in the alkali metals.