Observation of Microwave-Induced Magnetoresistance Oscillations in a ZnO/Mg x Zn1–x O Heterojunction

Abstract

Microwave-induced magnetoresistance and magnetoconductance oscillations in the two-dimensional electron system have been detected in a ZnO/MgxZn1–xO heterojunction. The structure has a high electron density of n = 6.5 × 1011 cm–2 and a very low mobility of 105 cm2 V–1 s–1. This clearly indicates that the mobility of two-dimensional electrons is not a critical parameter for the observation of microwave-induced oscillations. The samples were both Hall bars and Corbino disks. At least four oscillations have been resolved. Their amplitude increases with the magnetic field and all oscillations with numbers >1 have the same phase of 0.25. It has been shown that the microwave-induced photoelectromotive force is also a periodically oscillating function of the inverse magnetic field.