Crossover from weak localization to Shubnikov-de Haas oscillations in a high mobility 2D electron gas
Abstract
Description
We study the magnetoresistance, δρ_{xx}(B)/ρ_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 δρ_{xx}(B)/ρ_0 is governed by the interaction effects. Assuming short-range impurity scattering, we demonstrate that in the {\em second order} in the interaction parameter, $λ$, a {\em linear} B-dependence, δρ_{xx}(B)/ρ_0\sim λ^2ω_c/E_F with {\em temperature-independent} slope emerges in this domain of B (here ω_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.
4+ pages, 3 figures
4+ pages, 3 figures