Electron-Phonon Umklapp Interaction in the Low-Temperature Electrical Resistivity of Potassium

Abstract

It has long been postulated that, in those metals where the Fermi surface does not touch the Brillouin zone boundary, the electron-phonon umklapp scattering contribution to the electrical resistivity should rapidly disappear at sufficiently low temperatures. New experimental and theoretical evidence for such an effect is reported in the low-temperature electrical resistivity of potassium; the contribution from umklapp processes prevails over that of normal processes above ∼2.5°K, but decreases rapidly for temperatures below this.