Giant Magnetoresistance Oscillations Induced by Microwave Radiation and a Zero-Resistance State in a 2D Electron System with a Moderate Mobility

TL;DR

This study demonstrates that giant magnetoresistance oscillations and zero-resistance states can occur in a 2D electron system with moderate mobility under microwave radiation, expanding understanding beyond high-mobility systems.

Contribution

It shows that zero-resistance states are achievable in 2D electron systems with mobility below 10^6 cm^2/Vs under microwave irradiation, previously thought necessary for such phenomena.

Findings

Giant resistance oscillations observed at microwave frequencies 54-140 GHz.

Zero-resistance state appears near cyclotron resonance at 140 GHz.

Oscillations occur in systems with mobility lower than 10^6 cm^2/Vs.

Abstract

The effect of a microwave field in the frequency range from 54 to 140 $\mathrm{GHz}$ on the magnetotransport in a GaAs quantum well with AlAs/GaAs superlattice barriers and with an electron mobility no higher than $10^6$ $\mathrm{cm^2/Vs}$ is investigated. In the given two-dimensional system under the effect of microwave radiation, giant resistance oscillations are observed with their positions in magnetic field being determined by the ratio of the radiation frequency to the cyclotron frequency. Earlier, such oscillations had only been observed in GaAs/AlGaAs heterostructures with much higher mobilities. When the samples under study are irradiated with a 140-$\mathrm{GHz}$ microwave field, the resistance corresponding to the main oscillation minimum, which occurs near the cyclotron resonance, appears to be close to zero. The results of the study suggest that a mobility value lower than $10^6$ $\mathrm{cm^2/Vs}$ does not prevent the formation of zero-resistance states in magnetic field in a two-dimensional system under the effect of microwave radiation.