Non-linear response of a high mobility two-dimensional electron system near the second harmonic of the cyclotron resonance

TL;DR

This study investigates a unique photoresistivity peak near the second harmonic of cyclotron resonance in high-mobility 2D electron systems, revealing its nonlinear response to dc fields and challenging existing models.

Contribution

It provides the first detailed nonlinear transport measurements of the peak, showing its invariance to strong dc fields and highlighting the need for new theoretical explanations.

Findings

Peak can be induced by modest dc fields

Peak position remains unchanged under strong dc fields

Existing models cannot fully explain the observed behavior

Abstract

Recent experiments on microwave-irradiated high-mobility two-dimensional electron systems revealed a novel photoresistivity peak in the vicinity of the second cyclotron resonance harmonic. Here we report on the nonlinear transport measurements and demonstrate that the peak can be induced by modest dc fields and that its position is not affected even by strong dc fields, in contrast to microwave-induced resistance oscillations that shift to higher magnetic fields. These findings reinforce the notion that the peak cannot be described by existing models and provides important constraints for further theoretical considerations.