Simultaneous Measurements of Microwave Photoresistance and Cyclotron Reflection in the Multi-Photon Regime

TL;DR

This study simultaneously measures microwave photoresistance and plasmon-cyclotron resonance in high mobility GaAs/AlGaAs quantum wells, revealing multi-photon transitions and the role of plasmon coupling in reflection spectra.

Contribution

It demonstrates the first simultaneous measurement of photoresistance and cyclotron reflection in the multi-photon regime, highlighting plasmon coupling effects in reflection but not in conductivity.

Findings

Multi-photon transitions appear as sharp peaks in resistance and reflection.

Plasmon coupling influences cyclotron reflection but not electrical conductivity.

Higher carrier densities enhance multi-photon feature visibility.

Abstract

We simultaneously measure photoresistance with electrical transport and plasmon-cyclotron resonance (PCR) using microwave reflection spectroscopy in high mobility GaAs/AlGaAs quantum wells under a perpendicular magnetic field. Multi-photon transitions are revealed as sharp peaks in the resistance and the cyclotron reflection on samples with various carrier densities. Our main finding is that plasmon coupling is relevant in the cyclotron reflection spectrum but has not been observed in the electrical conductivity signal. We discuss possible mechanisms relevant to reflection or dc conductivity signal to explain this discrepancy. We further confirm a trend that higher order multi-photon features can be observed using higher carrier density samples.