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

Wang, Zhongchang; Zeng, Wen; Gu, Lin; Saito, Mitsuhiro; Tsukimoto, Susumu; Ikuhara, Yuichi

doi:10.1063/1.3516496

Cited by 53 publications

(45 citation statements)

References 55 publications

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“…However, recent advances in oxide heteroepitaxy, have made it possible to grow high-quality, single crystal anatase films on perovskite substrates such as SrTiO 3 (STO) or LaAlO 3 (LAO) [21,22]. This provides an excellent model system for controlled studies of the photocatalytic behavior of anatase under various conditions [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Band alignment and electronic structure of the anatase TiO2/SrTiO3(001) heterostructure integrated on Si(001)

et al. 2012

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Using density functional theory (DFT), scanning transmission electron microscopy (STEM), and electron energy loss spectroscopy (EELS) we study the interface structure and electronic properties of the anataseTiO 2 /SrTiO 3 (001) heterostructure epitaxially grown on Si (001) by molecular beam epitaxy (MBE). We show that charge transfer at the TiO 2 /SrTiO 3 interface is induced by the chemical bond formation between Ti and O. Subsequent O lattice polarization is found to be the leading screening mechanism at the interface. By comparing the theoretical local electronic structure to the O K edge EELS spectra taken at the interface with atomic resolution, we are able to trace how the local band structure evolves in response to the change in symmetry and bonding across the interface. We also discuss the effect of interfacial point defects (O vacancy and F impurity) on the band alignment.

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Section: Introductionmentioning

confidence: 99%

Band alignment and electronic structure of the anatase TiO2/SrTiO3(001) heterostructure integrated on Si(001)

et al. 2012

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“…In similarity with the LAO/STO heterostructure, the LaO-TiO 2 interface is more stable in the absence of oxygen vacancies, but with oxygen vacancies again the electrostatic energy makes up for the extra energy required to produce the Magneli-type defect [29] as shown in Table 1. We have calculated hollow and bridge stackings in both heterostructures and it turns out that in LAO/STO, the preferred one is the bridge position while in TiO 2 /LAO, the lowest energy configuration is the hollow one [26]. In the following, we show that this stacking difference brings about dramatic changes in the conducting properties.…”

Section: Effect Of Oxygen Vacancies At the Interfacial Tio 2 Layermentioning

confidence: 90%

Tuning the insulator-metal transition in oxide interfaces: An ab initio study exploring the role of oxygen vacancies and cation interdiffusion

Ferrari

Weissmann

2014

Phys. Status Solidi B

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We investigate the structural, electronic, and magnetic properties of a particular interface in the oxide heterostructures LaAlO3/SrTiO3 (LAO/STO) and TiO2‐anatase/LaAlO3 (TiO2/LAO), namely the interface of AlO2 facing TiO2, which is the energetically preferred one in the presence of interfacial oxygen vacancies. The optimum stacking for the ground state is different for each heterostructure with the interfacial Ti atoms being located either at hollow or bridge sites facing the AlO2 surface layer. This structural property determines the electronic character of the interface and as a consequence, in LAO/STO it is metallic while in TiO2/LAO it can be semiconducting and magnetic for a large concentration of vacancies. In addition, we find that cation interdiffusion at this interface is an energetically favored defect in both heterostructures with interfacial vacancies. Its main effect is to increase the size of the band gap in the semiconducting case and to open up a gap in the metallic one, thus allowing for a tuning of a metal to insulator transition.

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“…To ensure that the two sides of the interfacial slabs used in the calculations are thick enough to show a bulklike interior, the convergence of surface energy with respect to the slab layers was tested using the expressions given previously [41,42]. Two species of STO terminations (Fig.…”

Section: Calculated Structures and Properties Of Bulks And Surfacesmentioning

confidence: 99%

Structural and electronic impact of SrTiO3 substrate on TiO2 thin films

et al. 2012

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We demonstrate that the atomic structures, electronic states, and bonding nature of the interface between SrTiO 3 substrate and anatase TiO 2 thin films could be related and technologically manipulated at the atomic level. Applying advanced transmission electron microscopy, the grown anatase TiO 2 thin films are found to make a clean and direct contact to the SrTiO 3 substrates in an epitaxial, coherent, and atomically abrupt way. The atomic-resolution microscopic images reveal that the interface comprises SrO-terminated SrTiO 3 and Ti-terminated TiO 2 with the interfacial Ti of TiO 2 sitting above the hollow site, which is confirmed theoretically to be the most energetically favorable. Quantitatively, the first-principles calculations predict that the oxygen sublattice at the interface undergoes a notable reconstruction, i.e., the interfacial O atoms of TiO 2 are displaced largely toward the SrO plane of the SrTiO 3 , flattening the originally zigzag TiO 2 atomic chains. Consequently, the interfacial layers suffer a remarkable modification in the charge accumulation and also a deviation in the density of states from their bulk counterparts, indicating that the substrate can have an impact on the deposited thin films electronically. Using several analytic methods, the SrTiO 3 /TiO 2 interface is found to take on a metallic nature, and the interfacial bonding is determined to be of a mixed covalent and ionic character. This combined experimental and theoretical investigation gains insight into the complex atomic and electronic structures of the buried interface, which are fundamental for relating the atomic-scale structures to their properties on a quantum level.

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

Cited by 53 publications

References 55 publications

Band alignment and electronic structure of the anatase TiO2/SrTiO3(001) heterostructure integrated on Si(001)

Band alignment and electronic structure of the anatase TiO2/SrTiO3(001) heterostructure integrated on Si(001)

Tuning the insulator-metal transition in oxide interfaces: An ab initio study exploring the role of oxygen vacancies and cation interdiffusion

Structural and electronic impact of SrTiO3 substrate on TiO2 thin films

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