Atomic-scale structure and electronic property of the LaAlO3/TiO2 interface

Combining advanced transmission electron microscopy with high-precision first-principles calculation, atomic-scale structures of the LaAlO3/TiO2 interface are investigated and bridged to their electronic property at the atomic level. Experimentally, the deposited TiO2 thin film is demonstrated to have an anatase phase and bond directly to the LaAlO3 substrate in an epitaxial, coherent, and atomically abrupt fashion. The atomic-resolution microscopic images reveal that the interface can be terminated with either AlO2 or LaO layer, which is predicted in theory to exhibit a semiconducting or metallic nature at interface, respectively. By applying several analytic methods, we characterize carefully the electronic structure and determine interfacial bonding to be of a mixed covalent-ionic character. The combined experimental and theoretical studies performed shed light on the complex atomic and electronic structures of the buried interface, which are fundamental for understanding the promising properties of functional films for future electronics. c 2010 American Institute of Physics. [doi: 10.1063/1.3516496]