Positive Magnetoresistance of Composite Fermions in Laterally Modulated Structures

TL;DR

This paper explains the positive magnetoresistance and Weiss oscillations observed in modulated two-dimensional electron gases near filling factor 1/2 using a semi-classical approach based on composite fermions.

Contribution

It introduces a semi-classical Boltzmann equation method that accounts for higher-order effects in modulation strength to describe magneto-transport phenomena.

Findings

Strong positive magnetoresistance at low effective magnetic fields

Observation of Weiss oscillations in experiments

Theoretical explanation aligns with experimental data

Abstract

Adopting the mean-field composite fermion picture, we describe the magneto-transport properties of a two-dimensional electron gas with laterally modulated density around filling factor 1/2. The occurrence of a strong positive magnetoresistance at low effective magnetic fields as well as Weiss oscillations, which were observed in recent experiments in such systems, can be explained within a semi-classical Boltzmann equation approach, provided one goes beyond a second order approximation in the modulation strength.