RIPPLON-LIMITED MOBILITY OF SURFACE ELECTRONS ON THICK-FILMS OF HE-3 OVER HE-4

The electron mobility due to the scattering by ripplons is calculated for surface electrons localized over a thick layer enriched with He-3 above the He-3-He-4 mixture. The temperature-dependence of the mobilit y is determined for several thicknesses of the layer and small holding electric fields normal to the Liquid helium surface. The mobility of surface electrons over bulk pure He-3 is also considered, and the resu lts are in excellent agreement with the available experimental data, i n spite of the estimates of strong ripplon damping in He-3.