# Effect of illumination on quantum lifetime in GaAs quantum wells

## TL;DR

This study shows that low-temperature illumination significantly increases the quantum lifetime in GaAs quantum wells by redistributing charge and enhancing screening, which improves high-field magnetotransport properties.

## Contribution

It provides new insights into how illumination affects quantum lifetime and charge distribution in GaAs quantum wells, clarifying the underlying mechanism.

## Key findings

- Microwave resistance oscillation amplitude increases after illumination
- Quantum lifetime significantly improves post-illumination
- Charge redistribution enhances screening of doping layers

## Abstract

Low-temperature illumination of a two-dimensional electron gas in GaAs quantum wells is known to greatly improve the quality of high-field magnetotransport. The improvement is known to occur even when the carrier density and mobility remain unchanged, but what exactly causes it remains unclear. Here, we investigate the effect of illumination on microwave photoresistance in low magnetic fields. We find that the amplitude of microwave-induced resistance oscillations grows dramatically after illumination. Dingle analysis reveals that this growth reflects a substantial increase in the single-particle (quantum) lifetime, which likely originates from the light-induced redistribution of charge enhancing the screening capability of the doping layers.