Measurement of the anisotropic electron-phonon scattering rates in Al

From the linewidths of resonant transitions between surface Landau levels, we extract electron-phonon scattering rates at 13 Fermi-surface locations in Al. In the temperature range 2-10 K we find that the scattering rate varies by more than a factor of 10 over the Fermi surface, the highest rates being found near the Brillouin-zone boundaries. The observed scattering rates are compared with two recent theoretical calculations. Deviations are found, but the overall trend in the anisotropy is well predicted by both calculations. The present experiment does not confirm predicted departures from the usual $T^3$ scattering law.