Visible light enhanced field effect at LaAlO3/SrTiO3 interface

TL;DR

This study reveals that light illumination significantly enhances the electric field effect at the LaAlO3/SrTiO3 interface, leading to rapid and large resistance changes and increased carrier density, opening new avenues for device applications.

Contribution

It uncovers a novel light-enhanced field effect at the LaAlO3/SrTiO3 interface, demonstrating amplified and accelerated resistance and carrier density changes beyond traditional effects.

Findings

Light accelerates and amplifies the field-induced resistance growth.

Field-induced carrier density change exceeds capacitive expectations.

Resistance jump exceeds two orders of magnitude under illumination.

Abstract

Electrical field and light-illumination have been two most widely used stimuli in tuning the conductivity of semiconductor devices. Via capacitive effect electrical field modifies the carrier density of the devices, while light-illumination generates extra carriers by exciting trapped electrons into conduction band1. Here, we report on an unexpected light illumination enhanced field effect in a quasi-two-dimensional electron gas (q2DEG) confined at the LaAlO3/SrTiO3 (LAO/STO) interface which has been the focus of emergent phenomenon exploration2-14. We found that light illumination greatly accelerates and amplifies the field effect, driving the field-induced resistance growth which originally lasts for thousands of seconds into an abrupt resistance jump more than two orders of magnitude. Also, the field-induced change in carrier density is much larger than that expected from the capacitive effect, and can even be opposite to the conventional photoelectric effect. This work expands the space for novel effect exploration and multifunctional device design at complex oxide interfaces.