HAADF STEM and Ab Initio Calculations Investigation of Anatase TiO2/LaAlO3 Heterointerface

The understanding of the origin a two-dimensional electron gas (2DEG) at surface anatase TiO2 remains challenging issue. In particular, in ultra-thin films, it is extremely difficult to distinguish intrinsic effects, due physics TiO2, from extrinsic such as those arising structural defects, dislocations, and presence competing phases film/substrate interface. It is, therefore, mandatory unambiguously ascertain structure TiO2/substrate this work, by combining high angle annular dark-field scanning transmission microscopy (HAADF-STEM), density functional theory calculations, multislice image simulations, we have investigated nature strainless thin films grown on LaAlO3 substrate. oxygen vacancies has been proved stabilize formation an extra alloy layer, Ti2AlO4, means interface rearrangement. Our results, elucidate why growth directly substrate required deposition TiOx extra-layer 2DEG established, thus confirming absence critical thickness for its surface. These findings provide fundamental insights underlying mechanism TiO2/LAO hetero-interfaces engineer tailored applications.