Hard Materials Seminar - "Probing Oxide Surface Reconstruction by In-situ TEM"

Controlling the competition between localized and itinerant electrons is a central challenge in quantum oxides. Although ionic vacancies are widely recognized as electron/hole donors, identifying how local structural defect geometries determine whether electrons localize or remain itinerant has remained an open question—especially at complex surfaces. In this talk, new insights into the correlation between surface charge mobility and reconstruction captured via in-situ transmission electron microscopy will be presented. We identify a previously hidden structural degree of freedom beneath the surface, demonstrating how local geometric constraints govern the electron dichotomy. This work highlights surface/subsurface defect engineering as a powerful knob for tuning quantum states in complex oxides.