Phase of phonon-induced resistance oscillations in a high-mobility two-dimensional electron gas

TL;DR

This study investigates magnetoresistance oscillations caused by phonon interactions in high-mobility 2D electron gases, revealing a novel resonance condition that aligns with recent theories, differing from previous magnetophonon resonance observations.

Contribution

It experimentally demonstrates a new resonant condition for phonon-induced resistance oscillations, confirming recent theoretical predictions in high-mobility quantum wells.

Findings

Resonance maxima occur when phonon frequency exceeds an integer multiple of cyclotron frequency.

The observed resonance condition matches recent theoretical models.

Contrasts with previous experiments linking maxima to magnetophonon resonance.

Abstract

We report on experimental studies of magnetoresistance oscillations that originate from the resonant interaction of two-dimensional electrons with thermal transverse-acoustic phonons in very high-mobility GaAs/AlGaAs quantum wells. We find that the oscillation maxima consistently occur when a frequency of a phonon with twice the Fermi momentum exceeds an integer multiple of the cyclotron frequency. This observation is in contrast to to all previous experiments associating resistance maxima with magnetophonon resonance and its harmonics. Our experimentally obtained resonant condition is in excellent quantitative agreement with recent theoretical proposals.