Photo-current and photo-voltage oscillations in the two-dimensional electron system: screening and "anti-screening" of a potential profile

TL;DR

This paper reports on microwave-induced oscillations in photo-current and photo-voltage in 2D electron systems, revealing phenomena of screening and anti-screening of electric fields influenced by photo-excited electrons.

Contribution

It demonstrates the observation of oscillations related to screening effects in 2D electron systems under microwave irradiation, highlighting the interplay between microwave frequency and cyclotron resonance.

Findings

Oscillations pass zero near cyclotron resonance multiples

Oscillations linked to screening and anti-screening effects

Photo-signals originate from built-in electric fields

Abstract

We observe in state-of-the-art GaAs based 2D electron systems microwave induced photo-current and photo-voltage oscillations around zero as a function of the applied magnetic field. The photo-signals pass zero whenever the microwave frequency is close to a multiple of the cyclotron resonance frequency. They originate from built-in electric fields due to for instance band bending at contacts. The oscillations correspond to a suppression (screening) or an enhancement ("anti-screening") of these fields by the photo-excited electrons.