Hall detection of time-reversal symmetry breaking under AC electric driv ing

TL;DR

This paper investigates how AC electric fields affect time-reversal symmetry in a Hall bar, revealing deviations from reciprocity under inhomogeneous fields and preservation under homogeneous irradiation, supported by experimental and billiard model analysis.

Contribution

The study provides experimental evidence of time-reversal symmetry breaking under inhomogeneous AC fields and confirms its preservation under homogeneous irradiation in a GaAs Hall bar.

Findings

Strong deviations from reciprocity with inhomogeneous AC fields

Time-reversal symmetry preserved under homogeneous irradiation

Billiard model explains deviations and symmetry behavior

Abstract

In a four terminal sample microscopic time-reversibility leads to symmetry relations between resistance measurements where the role of current and voltage leads are exchanged. These reciprocity relations are a manifestation of general Onsager-Casimir symmetries in equilibrium systems. We investigate experimentally the validity of time reversal symmetry in a $GaAs/Ga_{1-x}Al_xAs$ Hall bar irradiated by an external AC field, at zero magnetic field. For inhomogeneous AC fields we find strong deviations from reciprocity relations and show that their origin can be understood from the the billiard model of a Hall junction. Under homogeneous irradiation the symmetry is more robust, indicating that time-reversal symmetry is preserved.