Temperature-Dependent Electrical Resistivity of Potassium below 2 K

Recent measurements of the temperature-dependent electrical resistivity ρT of potassium down to 1.1 K have indicated the presence of a possible new term ATⁿ, with $2>n>1$ and A∝ρ₀, the residual resistivity. We have measured ρT down to {} 0.5 K in order to confirm the existence of this term and to examine it more closely. We indeed find A∝ρ₀ and n1.5. We speculate that it arises from the electron-electron interaction modified by a size effect and possibly dislocation scattering.