Radiation-induced magnetoresistance oscillations in two-dimensional electron systems under bichromatic irradiation

TL;DR

This paper investigates how bichromatic radiation affects magnetoresistance oscillations in high-mobility two-dimensional electron systems, revealing suppression of certain peaks and emergence of new structures due to frequency mixing effects.

Contribution

It introduces a theoretical analysis of bichromatic irradiation effects on magnetoresistance oscillations using the balance-equation approach, highlighting new peak-valley structures and zero-resistance states.

Findings

Most characteristic peaks disappear under bichromatic irradiation.

New peak-valley structures emerge around frequencies related to photon mixing.

Some resistance minima become negative, indicating possible zero-resistance states.

Abstract

We analyze the magnetoresistance $R_{xx}$ oscillations in high-mobility two-dimensional electron systems induced by the combined driving of two radiation fields of frequency $\omega_1$ and $\omega_2$, based on the balance-equation approach to magnetotransport for high-carrier-density systems in Faraday geometry. It is shown that under bichromatic irradiation of $\omega_2\sim 1.5 \omega_1$, most of the characterstic peak-valley pairs in the curve of $R_{xx}$ versus magnetic field in the case of monochromatic irradiation of either $\omega_1$ or $\omega_2$ disappear, except the one around $\omega_1/\omega_c\sim 2$ or $\omega_2/\omega_c\sim 3$. $R_{xx}$ oscillations show up mainly as new peak-valley structures around other positions related to multiple photon processes of mixing frequencies $\omega_1+\omega_2$, $\omega_2-\omega_1$, etc. Many minima of these resistance peak-valley pairs can descend down to negative with enhancing radiation strength, indicating the possible bichromaticzero-resistance states.