New mechanism for a negative temperature derivative for the electrical resistivity of thin wires

It is shown that for thin wires of the alkali metals at low temperatures, normal electron-phonon scattering reduces the effectiveness of electron-surface scattering and thus leads to a negative temperature derivative for the electrical resistivity, d rho /dT<0. A calculation of d rho /dT is carried out and the results are found to be in satisfactory agreement with the recent low-temperature data of Yu et al. (1984) for thin wires of potassium.