Zero-resistance States Induced by Bichromatic Microwaves

TL;DR

This paper models the bichromatic microwave-induced resistance oscillations in a 2D electron gas, explaining the emergence of zero-resistance states and matching experimental observations through a comprehensive conductivity calculation.

Contribution

It introduces a theoretical model incorporating both microwave components, magnetic field, and impurity scattering to explain zero-resistance states in bichromatic photoresistance experiments.

Findings

Model reproduces experimental resistance oscillation features.

Superposition principle fails when zero-resistance states occur.

Negative resistance states transition into zero-resistance states via symmetry breaking.

Abstract

We have studied the bichromatic photoresistance states of a two dimensional electron gas in the regime of microwave induced resistance oscillations. Zudov and coworkers found clear experimental evidence of zero-resistance states by measuring the bichromatic resistance in a bidimensional gas of electrons. They found that the bichromatic resistance closely replicates the superposition of the two monochromatic components provided that both contributions are positive. However, the superposition principle is no longer valid if one of the two contributions give rice to a zero-resistance state. The experiments by Zudov and coworkers confirm that negative resistance states are rapidly driven into zero-resistance states through A. V. Andreev's symmetry breaking. In this work we present a model for the bichromatic-photoconductivity of a two dimensional electron system subjected to a uniform magnetic field. Our model includes both components of the microwave radiation, a uniform magnetic field and impurity scattering effects. The conductivity is calculated from a Kubo-like formula. Our calculations reproduce the main features of Zudov's experimental results.