Phonon-phonon scattering relaxation times for potassium

The relationship between the phonon-phonon scattering relaxation time and the electrical resistivity is analysed for the alkali metals. In particular, it is shown that the low-temperature resistivity data can be used to obtain the temperature dependence of the phonon-phonon scattering relaxation time for a specific region of the Brillouin zone. The analysis is applied to potassium. The phonon-electron scattering relaxation time of potassium is calculated and shown to be equal to the phonon-phonon scattering relaxation time at 12K for those phonons that dominate the low-temperature electrical resistivity. The present results are compared to other recent analyses of low-temperature phonon-phonon scattering for potassium.