Effect of rotation of the polarization of linearly polarized microwaves on the radiation-induced magnetoresistance oscillations

TL;DR

This study explores how rotating the polarization of linearly polarized microwaves affects magnetoresistance oscillations in GaAs/AlGaAs devices, revealing a sinusoidal dependence and frequency-dependent phase shifts.

Contribution

It demonstrates polarization sensitivity in microwave-induced magnetoresistance oscillations and uncovers a frequency-dependent phase shift phenomenon.

Findings

Resistance oscillations vary sinusoidally with polarization angle.

Maximal response phase shift depends on radiation frequency.

Polarization sensitivity is evident at low microwave power.

Abstract

Light-matter coupling is investigated by rotating, by an angle \theta, the polarization of linearly polarized microwaves with respect to the long-axis of GaAs/AlGaAs Hall-bar electron devices. At low microwave power, P, experiments show a strong sinusoidal variation in the diagonal resistance R_{xx} vs. \theta at the oscillatory extrema, indicating a linear polarization sensitivity in the microwave radiation-induced magnetoresistance oscillations. Surprisingly, the phase shift \theta_{0} for maximal oscillatory R_{xx} response under photoexcitation appears dependent upon the radiation-frequency f, the extremum in question, and the magnetic field orientation or sgn(B).