Quantisation of hopping magnetoresistance prefactor in strongly correlated two-dimensional electron systems

Abstract

We report an universal behaviour of hopping transport in strongly interacting mesoscopic two-dimensional electron systems (2DES). In a certain window of background disorder, the resistivity at low perpendicular magnetic fields follows the expected relation ρ ( B ⊥ ) = ρ B exp ( α B ⊥ 2 ) . The prefactor ρ B decreases exponentially with increasing electron density but saturates to a finite value at higher densities. Strikingly, this value is found to be universal when expressed in terms of absolute resistance and and shows quantisation at R B ≈ h / e 2 and R B ≈ 1 2 h / e 2 . We suggest a strongly correlated electronic phase as a possible explanation.