MANY-ELECTRON MAGNETOTRANSPORT IN 2D-ELECTRONS ON LIQUID-HELIUM

A many-electron theory of magnetotransport of a nondegenerate 2D elect ron system is presented along with experimental data in classically st rong and quantising magnetic fields. Due to the electron-electron inte raction each individual electron is driven by a fluctuating electric f ield E which converts the discrete Landau levels for non-interacting e lectrons, spacing HBARomega(c), into a continuous spectrum. Hence the classical magnetoresistance is very small (compared to the single-elec tron theory) until eER(c) < HBARomega(c) where R(c) is the classical L armor radius. At high magnetic fields, HBARomega(c) much greater than kT much greater than eEl (l = (HBAR/momega(c))1/2) for eEl/HBAR less t han the electron momentum scattering rate, the single-electron theory becomes valid. The onset field B0 for magnetoresistance lies in the ra nge 0.3-1.0 T for electrons on liquid helium. These many-electron effe cts have been observed experimentally near 1 K where the electron mobi lity is high and limited by He-4 vapor atoms and below 1 K in the ripp lon scattering regime.