The photoresponse of a two-dimensional electron gas at the second harmonic of the cyclotron resonance

TL;DR

This study investigates the photoresponse of a two-dimensional electron gas at the second harmonic of cyclotron resonance using terahertz spectroscopy, revealing the role of inhomogeneous electromagnetic fields at the sample boundary.

Contribution

It demonstrates the observation of the second harmonic of cyclotron resonance in a 2DEG and interprets its origin as due to high-frequency inhomogeneous fields at the sample edge.

Findings

Multiple magnetoplasmon resonances observed with dispersion relations

Second harmonic of cyclotron resonance detected and analyzed

Inhomogeneous electromagnetic fields influence the resonance appearance

Abstract

Terahertz spectroscopy experiments at magnetic fields and low temperatures were carried out on samples of different gate shapes processed on a high electron mobility GaAs/AlGaAs heterostructure. For a given radiation frequency, multiple magnetoplasmon resonances were observed with a dispersion relation described within a local approximation of the magnetoconductivity tensor. The second harmonic of the cyclotron resonance was observed and its appearance was interpreted as resulting from a high frequency, inhomogeneous electromagnetic field on the border of a two-dimensional electron gas with a metallic gate and/or an ohmic contact.