Terahertz photoresponse of a quantum Hall edge-channel diode

TL;DR

This study investigates the terahertz photoresponse of a quantum Hall edge-channel diode, revealing a resonant response and supporting a non-bolometric mechanism, with potential applications in THz detection.

Contribution

It introduces a novel edge-channel diode model for THz photoresponse in quantum Hall systems and demonstrates direct transport measurement between edge states.

Findings

Pronounced photo voltage at zero bias that decreases with external bias.

Resonant response allows extraction of a reduced effective cyclotron mass.

Supports a non-bolometric mechanism for the photo voltage.

Abstract

The Teraherz (THz) photoresponse of a two-dimensional electron gas in the quantum Hall regime is investigated. We use a sample structure which is topologically equivalent to a Corbino geometry combined with a cross-gate technique. This quasi-Corbino geometry allows us to directly investigate the THz-induced transport between adjacent edge-states, thus avoiding bulk effects. We find a pronounced photo voltage at zero applied bias, which rapidly decreases when an external current bias is applied. The photo voltage and its dependence on the bias current can be described using the model of an illuminated photodiode, resulting from the reconstruction of the Landau bands at the sample edge. Using the sample as a detector in a Fourier transform spectrometer setup, we find a resonant response from which we extract a reduced effective cyclotron mass. The findings support a non-bolometric mechanism of the induced photo voltage and the proposed edge-channel diode model.