Photovoltaic Oscillations Due to Edge-Magnetoplasmon Modes in a Very-High Mobility 2D Electron Gas

TL;DR

This study investigates microwave-induced photoresistance and photovoltaic oscillations in high-mobility 2D electron gases, revealing distinct bulk and edge oscillation behaviors and their independence from sample length.

Contribution

It provides experimental evidence that 1/B and B-oscillations are decoupled and occur in different regions, with B-oscillation periodicity independent of Hall bar length.

Findings

1/B oscillations occur in the bulk region.

B-oscillations occur along the edges.

B-oscillation periodicity is independent of Hall bar length.

Abstract

Using very-high mobility GaAs/AlGaAs 2D electron Hall bar samples, we have experimentally studied the photoresistance/photovoltaic oscillations induced by microwave irradiation in the regime where both 1/B and B-periodic oscillations can be observed. In the frequency range between 27 and 130 GHz we found that these two types of oscillations are decoupled from each other, consistent with the respective models that 1/B oscillations occur in bulk while the B-oscillations occur along the edges of the Hall bars. In contrast to the original report of this phenomenon (Ref. 1) the periodicity of the B-oscillations in our samples are found to be independent of L, the length of the Hall bar section between voltage measuring leads.