Magnetoconductance of two-dimensional electron systems in high magnetic fields

Abstract

The longitudinal conductivity σ xx of electrons on the surface of liquid helium was determined for magnetic fields up to 10 T, electron densities up to 4.8 × 10 8 cm −2 and temperatures around 1.7 K. All measurements follow the Drude-Lorentz model 1/ σ xx ∼ B 2 up to field values for which μ s B ≈ 3. In the quantum limit ( h ̵ ω c ⪢ kT) a 1/σ xx ∼ √B behavior is observed down to h ̵ ω c = kT for the highest density. From these results we estimated a high-field mobility. For densities below 10 8 cm −2 existing theories fit our data in almost the full field range. For higher densities the existing theories describe the magnetoconductivity only in the low-field range using the zero-field mobility as fit-parameter and lead to zero-field mobilities which are in agreement with earlier measurements.