The temperature dependent thermal and electrical resistivity of high purity silver from 2 to 20 K

The low temperature (T), temperature dependent electrical resistivity (?), and thermal resistivity (ω), have been measured in a sample having a residual resistivity ratio of 10,000: 1. Below approximately 10 K ? ∝ T⁵ and ω ∝ T² — in excellent agreement with theory. Both resistivities are considerably smaller than those obtained by previous workers on less pure samples. Above 10 K the resistivities rise more rapidly with temperature — particularly for ω. The experimentally determined temperature dependent Lorenz number, $\text{L}{}_{\mathrm{i}}\text{=}\text{?}\text{ωT}$ is examined and suggests that the augmentation of the horizontal scattering of electrons by umklapp processes is greater for ω than for ?.