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

TL;DR

This study reports a large, non-saturating positive magneto-resistance in high mobility 2D electron gases, explained by the interplay of short and long-range disorder potentials, supported by experimental data and theoretical modeling.

Contribution

It demonstrates the role of combined short and long-range disorder in causing large positive magneto-resistance in high mobility 2D electron gases, aligning with recent theoretical predictions.

Findings

Magneto-resistance increases with magnetic field as B^α, with α between 0.9 and 1.2.

Non-monotonic magneto-resistance observed in antidot lattices.

Experimental results agree qualitatively with Polyakov et al.'s theory on disorder interplay.

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 $\rho_{xx}\sim B^{\alpha} (\alpha=0.9-1.2)$. 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.