Two-Dimensional Charge Localization at the Perovskite Oxide Interface

TL;DR

This study reveals that 2D electrons at the LaAlO3/SrTiO3 interface are localized in hybridized states, with localization influenced by temperature and gating, emphasizing the role of interfacial hybridization in charge dynamics.

Contribution

It provides experimental evidence that interfacial hybridization critically governs 2D charge localization at oxide interfaces, advancing understanding beyond disorder effects.

Findings

Localization occurs in hybridized states at the interface.

Temperature reduction and ionic liquid gating induce localization.

Hybridization plays a key role in charge dynamics.

Abstract

The effects of atomic-scale disorder and charge (de)localization holds significant importance,and they provide essential insights in unravelling the role that strong and weak correlations play in condensed matter systems.For perovskite oxide heterostructures,while disorders introduced via various external stimuli have strong influences on the (de)localization of the interfacial two-dimensional (2D) electrons, these factors alone could not fully account for the system's charge dynamics where interfacial hybridization holds very strong influence.Here, we determine that the displaced 2D free electrons are localized in the specific hybridized states at the LaAlO3/SrTiO3(LAO/STO) interface.This experimental study combines both transport measurements and temperature-dependent X-ray absorption spectroscopy and suggests the localization of 2D electrons can be induced via temperature reduction or ionic liquid gating and it applies to both amorphous and crystalline interfacial systems.Specifically, we demonstrate that interfacial hybridization plays a pivotal role in regulating the 2D electron localization effects.Our study resolves the location where the 2D electrons are localized and highlights the importance of interfacial hybridization and opens further scientific investigation of its influence on 2D charge localization in oxide heterointerfaces.