Magnetoresistivity of a weakly-screened, low-density, two-dimensional electron liquid

Abstract

We probe the strength of electron-electron interactions at intermediate magnetic fields in the classical regime using magnetoconductivity measurements of two-dimensional, non-degenerate electrons on liquid helium. We span both the independent-electron regime, where the data are qualitatively described by the self-consistent Born approximation (SCBA), and the strongly-interacting electron (Drude) regime. We observe a crossover from SCBA to Drude theory at finite magnetic fields as a function of electron density. The SCBA magnetoresistance is found to be density dependent. Our data confirm the theory for magnetoresistivity in a weakly screened, two-dimensional electron gas, and demonstrate that electron-electron interactions are important to very low densities.