Sharp magnetic field dependence of the two-dimensional Hall coefficient induced by classical memory effects

摘要

We show that a sharp dependence of the Hall coefficient R on the magnetic field B arises in two-dimensional electron systems with strong scatterers. The phenomenon is due to classical memory effects. We analytically calculate the dependence of R on B for the case of scattering by antidots (modeled by hard disks of radius a), randomly distributed with a concentration n_01/a~2. We demonstrate that in very weak magnetic fields (ω_cT_(tr) ≤ n_0a~2), memory effects lead to a considerable renormaJization of the Boltzmann value of the Hall coefficient: δSR/R ～ 1. With increasing magnetic field, the relative correction to R decreases, then changes sign, and saturates at the value δR/R～-n_0a~2. We also discuss the effect of smooth disorder on the dependence of R on B.