title: Comparison Studies of Interfacial Electronic and Energetic Properties of LaAlO3/TiO2and TiO2/LaAlO3Heterostructures from First-Principles Calculations.
abstract: By using first-principles electronic structure calculations, we studied electronic and energetic properties of perovskite oxide heterostructures with different epitaxial growth order between anatase TiO2and LaAlO3. Two types of heterostructures, i.e., TiO2film grown on LaAlO3substrate (TiO2/LaAlO3) and LaAlO3film grown on TiO2substrate (LaAlO3/TiO2), were modeled. The TiO2/LaAlO3model is intrinsically metallic and thus does not exhibit an insulator-to-metal transition as TiO2film thickness increases; in contrast, the LaAlO3/TiO2model shows an insulator-to-metal transition as the LaAlO3film thickness increases up to 4 unit cells. The former model has a larger interfacial charge carrier density (n ∼ 1014cm-2) and smaller electron effective mass (0.47me) than the later one (n ∼ 1013cm-2, and 0.70me). The interfacial energetics calculations indicate that the TiO2/LaAlO3model is energetically more favorable than the LaAlO3/TiO2model, and the former has a stronger interface cohesion than the later model. This research provides fundamental insights into the different interfacial electronic and energetic properties of TiO2/LaAlO3and LaAlO3/TiO2heterostructures.
authors.affiliation: Department of NanoEngineering, University of California, San Diego , 9500 Gilman Drive, Mail Code 0448, La Jolla, California 92093-0448, United States.
authors.forename: Jianli
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of NanoEngineering, University of California, San Diego , 9500 Gilman Drive, Mail Code 0448, La Jolla, California 92093-0448, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of NanoEngineering, University of California, San Diego , 9500 Gilman Drive, Mail Code 0448, La Jolla, California 92093-0448, United States.
authors.forename: Kesong
authors.identifier: http://orcid.org/0000-0002-9691-0636
authors.initials: K
authors.lastname: Yang
keywords: anatase TiO2; conductivity; interfacial energetics; oxide heterostructures; two-dimensional electron gas