We study the magnetoresistance of an ultrahigh mobility GaAs/AlGaAs two-dimensional electron sample in a weak magnetic field under low-frequency (f < 20 GHz) microwave (MW) irradiation. We observe that with decreasing MW frequency, microwave induced resistance oscillations (MIRO) damp and multi-photon processes become dominant. At very low MW frequency (f < 4 GHz), MIRO disappears gradually and a new SdH-like oscillation develops. The analysis indicates that the new oscillation may originate from alternating Hall-field induced resistance oscillations (ac-HIRO), or can be viewed as a multi-photon process of MIRO in low MW frequency limit. Our findings bridge the non-equilibrium states of MIRO and HIRO, which can be brought into a frame of quantum tunneling junction model.
@article{arxiv.1708.08498,
title = {Low-Frequency Microwave Induced Quantum Oscillations in A Two-Dimensional Electron System},
author = {Jian Mi and Huiying Liu and Junren Shi and L. N. Pfeiffer and K. W. West and K. W. Baldwin and Chi Zhang},
journal= {arXiv preprint arXiv:1708.08498},
year = {2019}
}