Magnetic field asymmetry of mesocopic dc rectification in Aharonov Bohm rings

TL;DR

This paper investigates the nonlinear dc conductance of mesoscopic rings, revealing magnetic field asymmetry in second-order responses linked to electron interactions, challenging traditional symmetry rules.

Contribution

It demonstrates the existence of magnetic field asymmetry in nonlinear conductance of mesoscopic rings, aligning with recent theories on electron interactions beyond linear response.

Findings

Second-order conductance response shows magnetic field asymmetry.

Asymmetry depends on conductance variations over an order of magnitude.

Results agree with theoretical predictions relating asymmetry to electron interactions.

Abstract

Fundamental Casimir-Onsager symmetry rules for linear response do not apply to non linear transport. This motivates the investigation of nonlinear dc conductance of mesoscopic GaAs/GaAlAs rings in a 2 wire configuration. The second order current response to a potential bias is of particular interest. It is related to the sensitivity of conductance fluctuations to this bias and contains information on electron interactions not included in the linear response. In contrast with the linear response which is a symmetric function of magnetic field we find that this second order response exhibits a field dependence which contains an antisymmetric part. We analyse the flux periodic and aperiodic components of this asymmetry and find that they only depend on the conductance of the rings which is varied by more than an order of magnitude. These results are in good agreement with recent theoretical predictions relating this asymmetric response to the electron interactions.