Crossover from weak localization to Shubnikov-de Haas oscillations in a high mobility 2D electron gas

TL;DR

This paper investigates the magnetoresistance behavior of high-mobility 2D electron gases, revealing a linear B-dependence caused by impurity scattering effects in an intermediate magnetic field regime.

Contribution

It demonstrates that a second-order interaction effect leads to a temperature-independent linear magnetoresistance in a specific magnetic field domain.

Findings

Linear B-dependence of magnetoresistance observed

Originates from impurity scattering and Friedel oscillations

Independent of full Larmor circle execution

Abstract

We study the magnetoresistance, \delta\rho_{xx}(B)/\rho_0, of a high-mobility 2D electron gas in the domain of magnetic fields, B, intermediate between the weak localization and the Shubnikov-de Haas oscillations, where \delta\rho_{xx}(B)/\rho_0 is governed by the interaction effects. Assuming short-range impurity scattering, we demonstrate that in the {\em second order} in the interaction parameter, $\lambda$, a {\em linear} B-dependence, \delta\rho_{xx}(B)/\rho_0\sim \lambda^2\omega_c/E_F with {\em temperature-independent} slope emerges in this domain of B (here \omega_c and E_F are the cyclotron frequency and the Fermi energy, respectively). Unlike previous mechanisms, the linear magnetoresistance is {\em unrelated} to the electron executing the full Larmour circle, but rather originates from the impurity scattering via the B-dependence of the {\em phase} of the impurity-induced Friedel oscillations.