  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.
