Photo-Conductivity Response at Cyclotron-Resonance Harmonics in a Non-Degenerate 2D Electron Gas on Liquid Helium

TL;DR

This study reports the first observation of oscillatory photo-conductivity at cyclotron-resonance harmonics in a non-degenerate 2D electron system on liquid helium, revealing new insights into electron-photon interactions.

Contribution

It provides the first experimental evidence of oscillatory photo-conductivity at cyclotron harmonics in a non-degenerate 2D electron system on liquid helium, supported by theoretical analysis.

Findings

Detected dc conductivity oscillations at cyclotron-resonance harmonics

Oscillation period governed by microwave to cyclotron frequency ratio

Explained by oscillatory correction to electron distribution due to photon-assisted scattering

Abstract

We report the first observation of an oscillatory photo-conductivity response at the cyclotron-resonance harmonics in a non-degenerate 2D electron system formed on the free surface of liquid helium. The dc conductivity oscillations are detected for electrons occupying the ground surface subband. Their period is governed by the ratio of the microwave frequency to the cyclotron frequency. Theoretical analysis of the photo-response in a strongly interacting electron system indicates that the observation can be explained by an oscillatory correction to the electron distribution function that appears for a large inelastic relaxation time because of photon-assisted scattering.