Microwave-induced zero-resistance states in a high-mobility two-subband electron system

TL;DR

This paper investigates microwave-induced zero-resistance states in a high-mobility two-subband electron system, revealing unique interference effects and an unknown damping mechanism affecting magneto-intersubband oscillations.

Contribution

It demonstrates the coexistence of MIRO and MISO in a two-subband system and uncovers an unknown damping mechanism affecting MISO at low magnetic fields.

Findings

Observation of microwave photoresistance at high MISO oscillations

MIRO appears at lower magnetic fields than MISO

Zero resistance states occur near MISO maxima under microwave irradiation

Abstract

In this study we used selectively-doped GaAs/AlAs heterostructure to fabricate a high-mobility two-subband electronic system with substantially different concentration of electrons in subbands. We observe microwave photoresistance at high numbers of magneto-intersubband oscillations (MISO). The system under study demonstrates microwave-induced resistance oscillations (MIRO) and MISO interference. MIRO in the studied two-subband system appear in lower magnetic fields comparing to MISO. This is an indication of some unknown mechanism that exists in the two-subband system and is responsible for MISO amplitude damping in low magnetic fields, while it does not affect the MIRO amplitude. Zero resistance states (ZRS) appear in the system under study under microwave irradiation in the narrow range of magnetic fields near the MISO maximum.