Influence of a Parallel Magnetic Field on Microwave Photoconductivity in a High-Mobility 2D Electron System

TL;DR

This study experimentally investigates how a parallel magnetic field affects microwave-induced resistance oscillations and zero-resistance states in high-mobility 2D electron systems, revealing suppression of MIRO/ZRS and enhancement of magnetoplasmon resonance.

Contribution

It provides new experimental insights into the contrasting effects of a parallel magnetic field on MIRO/ZRS and MPR, challenging existing theoretical models.

Findings

MIRO/ZRS are strongly suppressed by a modest parallel magnetic field.

Magnetoplasmon resonance is enhanced by the parallel magnetic field.

Current models do not account for the contrasting effects observed.

Abstract

We have studied experimentally the influence of a parallel magnetic field ($B_{//}$) on microwave-induced resistance oscillations (MIRO) and zero-resistance states (ZRS) previously discovered in a high-mobility 2D electron system. We have observed a strong suppression of MIRO/ZRS by a modest $B_{//}\sim 0.5$ T. In Hall bar samples, magnetoplasmon resonance (MPR) has also been observed concurrently with the MIRO/ZRS. In contrast to the suppression of MIRO/ZRS, the MPR peak is found to be enhanced by $B_{//}$. These findings have not been addressed by current models proposed to explain the microwave-induced effects.