Oxygen Vacancies on SrO-terminated SrTiO3(001) Surfaces studied by Scanning Tunneling Spectroscopy

Abstract

The electronic structure of SrTiO3(001) surfaces was studied using scanning tunneling spectroscopy and density-functional theory. With high dynamic range measurements, an in-gap transition level was observed on SrO-terminated surfaces, at 2.7 eV above the valence band maximum. The density of centers responsible for this level was found to increase with surface segregation of oxygen vacancies and decrease with exposure to molecular oxygen. Based on these finding, the level is attributed to surface O vacancies. A level at a similar energy is predicted theoretically on SrO-terminated surfaces. For TiO2-terminated surfaces, no discrete in-gap state was observed, although one is predicted theoretically. This lack of signal is believed to be due to the nature of defect wavefunction involved, as well as the possible influence of transport limitations in the tunneling spectroscopy measurements.

17 pages, 8 figures

References in corpus (7)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Magnetic effects at the interface between nonmagnetic oxides
• High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives
• Origin of Metallic States at Heterointerface between Band Insulators LaAlO${}_3$ and SrTiO${}_3$
• Polar catastrophe and electronic reconstructions at the LaAlO3/SrTiO3 interface: evidence from optical second harmonic generation
• Atomically precise interfaces from non-stoichiometric deposition
• A survey of fractured SrTiO${}_3$ surfaces: from the micro-meter to nano-meter scale

Cited by in corpus (4)

• Oxygen vacancies in strained SrTiO${}_3$ thin films: formation enthalpy and manipulation
• Interface exchange processes in LaAlO${}_3$/SrTiO${}_3$ induced by oxygen vacancies
• Dichotomy of the Photo Induced 2-Dimensional Electron Gas on SrTiO${}_3$ Surface Terminations
• Growth and electronic properties of nanolines on TiO2-terminated SrTiO3(001) surfaces