MAGNETOCONDUCTANCE OF ELECTRONS ON LIQUID-HELIUM IN THE EXTREME QUANTUM LIMIT

Measurements of the longitudinal magnetoconductivity sigma(xx) of the nondegenerate two-dimensional system of electrons on the surface of li quid helium are presented for magnetic fields up to 22 T in the temper ature range 0.4 K < T < 2.1 K. For temperatures above 1.6 K our experi mental results are in good agreement with a quantum magnetotransport t heory of short-range scattering within broadened Landau levels. If the temperature is reduced below 1.5 K, a deviation of the experimental d ata from the theoretical calculations is observed for magnetic fields between 2 T and 10 T. At temperatures T < 0.8 K where the conductivity of the surface electrons is determined by the scattering between elec trons and ripplons, the magnetic field dependence of our measurements of 1/sigma(xx) (B) for high fields is rather poorly reproduced by the existing theories.