de Haas-van Alphen measurements of the scattering of conduction electrons from hydrogen in copper

De Haas-van Alphen Dingle temperatures for the scattering of conduction electrons from hydrogen in copper have been measured for the first time in a metal-hydrogen system. Special care was attributed to the sample preparation to ensure a random distribution of the hydrogen in the copper lattice. The strongest scattering rates are observed at the necks of the Fermi surface and the weakest in the belly regions being smaller here by a factor of 3.3. The observed anisotropy of the scattering gives strong indication that the hydrogen occupies octahedral interstices in the fcc copper lattice. The data have been analyzed in terms of Friedel phase shifts according to a theory by Holzwarth and Lee. The $s$ phase shift is the dominant one, the $p$ phase shift is about an order of magnitude smaller and the $d$ phase shifts are negligible. This is a consequence of the short range of the hydrogen potential located at an octahedral interstice. Backscattering is found to give an essential contribution to the Friedel phase shifts. A recent average-$t$-matrix approximation (ATA) calculation for CuH by Huisman and Weiss predicts scattering rates in excellent agreement with the experiment. The descriptions of the electron scattering by ATA and by phase-shift analysis are compared for CuH. A model calculation is proposed which allows to find out how far backscattering is included in the ATA calculations.