Magnetic field symmetry and phase rigidity of the nonlinear conductance in a ring

TL;DR

This study investigates the magnetic field symmetry and phase behavior of nonlinear conductance in a semiconductor Aharonov-Bohm ring, revealing tunable asymmetries and phase non-rigidity in nonlinear transport.

Contribution

It demonstrates that the phase of nonlinear conductance in a two-terminal ring is tunable and not rigid, contrasting with linear conductance behavior.

Findings

Voltage-symmetric conductance is symmetric in magnetic field.

Voltage-antisymmetric conductance is asymmetric and tunable.

Nonlinear conductance phase is not rigid and can be controlled by gate voltages.

Abstract

We have performed nonlinear transport measurements as a function of a perpendicular magnetic field in a semiconductor Aharonov-Bohm ring connected to two leads. While the voltage-symmetric part of the conductance is symmetric in magnetic field, the voltage-antisymmetric part of the conductance is not symmetric. These symmetry relations are compatible with the scattering theory for nonlinear mesoscopic transport. The observed asymmetry can be tuned continuously by changing the gate voltages near the arms of the ring, showing that the phase of the nonlinear conductance in a two-terminal interferometer is not rigid, in contrast to the case for the linear conductance.