MANY-ELECTRON MAGNETOCONDUCTIVITY OF 2D ELECTRONS ON LIQUID-HELIUM

The magnetoconductivity sigma(B) of 2D electrons on liquid helium was measured from 0.25 K to 1.30 K in the electron fluid phase in magnetic fields B less than or equal to 8 Tesla. In low fields the Drude model holds even for mu B >> 1. At higher fields sigma(B) becomes density d ependent. The Drude behaviour and the density dependence are due to ma ny-electron effects where cyclotron orbit diffusion is controlled by i nternal electric fields. The density and temperature dependence of the se internal fields derived from experiments are in good agreement with Monte Carlo simulations.