Surface scattering of electrons on copper whiskers and its influence on the electrical resistivity at 4.2 K

Abstract

The effect of specimen size on the electrical resistivity at 4.2 K of copper whiskers having transverse dimensions in the order of the electron mean-free path was measured. The experimental data are interpreted by means of a modified Nordheim formula adapted to the exact theory of Dingle. Assuming for copper the value of the productQ ₀·λ obtained from the free electron model a specularity parameterp for the surface scattering of conduction electrons is deduced from the diameter dependence of the sample resistivity. Values ofp=0.45 (up to 0.66 in an individual case) andp=0.18 are calculated exhibiting that significant specular reflection is present. Differences in the amount of specular reflection appear to arise from differences in the microscopically observed surface conditions of the whiskers.