Seebeck effect in the conducting LaAlO_{3}/SrTiO_{3} interface

Abstract

The observation of metallic behavior at the interface between insulating oxides has triggered worldwide efforts to shed light on the physics of these systems and clarify some still open issues, among which the dimensional character of the conducting system. In order to address this issue, we measure electrical transport (Seebeck effect, Hall effect and conductivity) in LaAlO_{3}/SrTiO_{3} interfaces and, for comparison, in a doped SrTiO_{3} bulk single crystal. In these experiments, the carrier concentration is tuned, using the field effect in a back gate geometry. The combined analysis of all experimental data at 77 K indicates that the thickness of the conducting layer is ~7 nm and that the Seebeck effect data are well described by a two-dimensional (2D) density of states. We find that the back gate voltage is effective in varying not only the charge density, but also the thickness of the conducting layer, which is found to change by a factor of ~2, using an electric field between -4 and +4MV/m at 77K. No enhancement of the Seebeck effect due to the electronic confinement and no evidence for two-dimensional quantization steps are observed at the interfaces.

15 pages, 5 figures

References in corpus (6)

• Magnetic effects at the interface between nonmagnetic oxides
• High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Dynamical response and confinement of the electrons at the LaAlO3/SrTiO3 interface
• Modulation Doping of a Mott Quantum Well by a Proximate Polar Discontinuity
• Electronic Interface Reconstruction at Polar-Nonpolar Mott Insulator Heterojunctions

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• Efficient intrinsic spin-to-charge current conversion in an all-epitaxial single-crystal perovskite-oxide heterostructure of La0.67Sr0.33MnO3/LaAlO3/SrTiO3
• First-principles modeling of the thermoelectric properties of SrTiO${}_3$/SrRuO${}_3$ superlattices
• Large band offset as driving force of 2-dimensional electron confinement: the case of SrTiO${}_3$/SrZrO${}_3$ interface
• Large phonon-drag enhancement induced by narrow quantum confinement at the LaAlO3/SrTiO3 interface
• Anomalous transport near the Lifshitz transition at the LaAlO${}_3$/SrTiO${}_3$ interface
• Detailed investigation of the phase transition in K${}_x$P${}_4$W${}_8$O${}_{32}$ and experimental arguments for a charge density wave due to hidden nesting
• Transport and thermoelectric properties of the LaAlO${}_3$/SrTiO${}_3$ interface
• Influence of gas ambient on charge writing at the LaAlO3/SrTiO3 heterointerface
• Polarity-field driven conductivity in SrTiO${}_3$/LaAlO${}_3$: a hybrid functional study
• δ-doped LaAlO3-SrTiO3 interface: Electrical transport and characterization of the interface potential
• Coupling between tilts and charge carriers at polar-nonpolar perovskite interfaces