Large positive magneto-resistance in high mobility 2D electron gas : interplay of short and long range disorder

Abstract

We have observed a large positive quasi-classical magneto-resistance (MR) in a high mobility 2D electron gas in AlGaAs/GaAs heterostructure. The magneto-resistance is non-saturating and increases with magnetic field as $ρ_{xx}\sim B^α (α=0.9-1.2)$. In antidot lattices a non-monotonic MR is observed. We show that in both cases this MR can be qualitatively described in terms of the theory recently advanced by Polyakov et al (PRB, 64, 205306 (2001)). Their prediction is that such behavior as we observe may be the consequence of a concurrent existence of short and long range scattering potentials.