Band offsets and density of Ti3+ states probed by X-ray photoemission on LaAlO3/SrTiO3 heterointerfaces and their LaAlO3 and SrTiO3 bulk precursors

Abstract

A set of LaAlO3/SrTiO3 (LAO-STO) interfaces has been probed by X-ray photoemission spectroscopy in order to contrast and compare the effects of LAO overlayer thickness and of the growth conditions on the electronic properties of these heterostructures. These effects are tracked by considering the band-offset and the density of Ti3+ states, respectively. It is shown that the dominant effects on the local electronic properties are determined by the O2 partial pressure during the growth. In particular, a low P(O2) yields Ti3+ states with higher density and lower binding energy as compared to the sample grown at high P(O2) or to the bare STO reference sample. Band offset effects are all below about 0.7 eV, but a careful analysis of Ti 2p and Sr 3d peaks shows that valence band offsets can be at the origin of the observed peak width. In particular, the largest offset is shown by the conducting sample, that displays the largest Ti 2p and Sr 3d peak widths.

arXiv commentSubmitted to Physical Review B, revised version

References in corpus (13)

• Magnetic effects at the interface between nonmagnetic oxides
• Why Some Interfaces Cannot be Sharp
• High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Mapping the Spatial Distribution of Charge Carriers in LaAlO3/SrTiO3 Heterostructures
• Avoiding the polarization catastrophe in LaAlO3 overlayers on SrTiO3(001) through a polar distortion
• Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures by hard X-ray photoelectron spectroscopy
• Instability, Intermixing and Electronic Structure at the Epitaxial LaAlO3/SrTiO3(001) Heterojunction
• High-transition-temperature superconductivity in the absence of the magnetic-resonance mode
• Origin of Metallic States at Heterointerface between Band Insulators LaAlO${}_3$ and SrTiO${}_3$
• Multiple conducting carriers generated in LaAlO3/SrTiO3 heterostructures
• Electronic charges and electric potential at LaAlO3/SrTiO3 interfaces studied by core-level photoemission spectroscopy
• Electronic properties of buried hetero-interfaces of LaAlO3 on SrTiO3

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• Band inversion driven by electronic correlations at the (111) LaAlO${}_3$/SrTiO${}_3$ interface
• Metal/SrTiO${}_3$ two-dimensional electron gases for spin-to-charge conversion
• Metallic Conductance at the Interface of Tri-color Titanate Superlattices
• Observation of strontium segregation in LaAlO${}_3$/SrTiO${}_3$ and NdGaO${}_3$/SrTiO${}_3$ oxide heterostructures by X-ray photoemission spectroscopy
• Influence of oxygen pressure and aging on LaAlO3 films grown by pulsed laser deposition on SrTiO3 substrates
• Scalable $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3-\mathrm{Ti}{\mathrm{O}}_2$ Conductive Oxide Interfaces as Defect Reservoirs for Resistive Switching Devices
• Transport in strongly-coupled graphene-LaAlO3/SrTiO3 hybrid systems