Magnetic-field asymmetry of nonlinear mesoscopic transport

TL;DR

This paper explores how nonlinear electronic transport in mesoscopic systems exhibits magnetic-field asymmetry due to screening potential effects, challenging the traditional Onsager relations in the nonlinear regime.

Contribution

It demonstrates that nonlinear current-voltage characteristics are not symmetric in magnetic field because of screening potential dependence, supported by models of quantum Hall and chaotic cavities.

Findings

Nonlinear conductance asymmetry arises from screening potential effects.

Asymmetry in chaotic cavity conductance fluctuations diminishes with contact size.

The study provides theoretical insights into nonlinear transport deviations from Onsager relations.

Abstract

We investigate departures of the Onsager relations in the nonlinear regime of electronic transport through mesoscopic systems. We show that the nonlinear current--voltage characteristic is not an even function of the magnetic field due only to the magnetic-field dependence of the screening potential within the conductor. We illustrate this result for two types of conductors: A quantum Hall bar with an antidot and a chaotic cavity connected to quantum point contacts. For the chaotic cavity we obtain through random matrix theory an asymmetry in the fluctuations of the nonlinear conductance that vanishes rapidly with the size of the contacts.