Gauge invariant nonlinear electric transport in mesoscopic conductors

TL;DR

This paper investigates the nonlinear electric transport in mesoscopic conductors using the scattering approach, emphasizing gauge invariance and self-consistent potentials, with applications to quantum point contacts and resonant levels.

Contribution

It introduces a gauge-invariant framework for analyzing nonlinear transport in mesoscopic systems, incorporating self-consistent potentials and charge conservation.

Findings

Rectification coefficient of a quantum point contact analyzed.

Nonlinear I-V characteristic of a resonant level studied.

Gauge invariance ensures physical consistency of the nonlinear response.

Abstract

We use the scattering approach to investigate the nonlinear current-voltage characteristic of mesoscopic conductors. We discuss the leading nonlinearity by taking into account the self-consistent nonequilibrium potential. We emphasize conservation of the overall charge and current which are connected to the invariance under a global voltage shift (gauge invariance). As examples, we discuss the rectification coefficient of a quantum point contact and the nonlinear current-voltage characteristic of a resonant level in a double barrier structure.