Electron transfer and ionic displacements at the origin of the 2D electron gas at the LAO/STO interface: Direct measurements with atomic-column spatial resolution

Abstract

The discovery that the interface between two band gap insulators LaAlO3 and SrTiO3 is highly conducting has raised an enormous interest in the field of oxide electronics. The LAlO3/SrTiO3 interface can be tuned using an electric field and switched from a superconducting to an insulating state. Conducting paths in an insulating background can be written applying a voltage with the tip of an atomic force microscope, creating great promise for the development of a new generation of nanoscale electronic devices. However, the mechanism for interface conductivity in LaAlO3/SrTiO3 has remained elusive. The theoretical explanation based on an intrinsic charge transfer (electronic reconstruction) has been strongly challenged by alternative descriptions based on point defects. In this work, thanks to modern aberration-corrected electron probes with atomic-scale spatial resolution, interfacial charge and atomic displacements originating the electric field within the system can be simultaneously measured, yielding unprecedented experimental evidence in favor of an intrinsic electronic reconstruction.

Accepted for publication in Advanced Materials. Published online on 06/20/2012

References in corpus (2)

• Avoiding the polarization catastrophe in LaAlO3 overlayers on SrTiO3(001) through a polar distortion
• Polar catastrophe and electronic reconstructions at the LaAlO3/SrTiO3 interface: evidence from optical second harmonic generation

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• Polar Metals Taxonomy for Materials Classification and Discovery
• Competition between covalent bonding and charge transfer at complex-oxide interfaces
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• Thickness Dependent Carrier Density at the Surface of SrTiO3 (111) Slabs
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• Ferroelectric Exchange Bias Affects Interfacial Electronic States
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• Tuning two-dimensional electron (hole) gases at LaInO${}_3$/BaSnO${}_3$ interfaces: Impact of polar distortions, termination, and thickness
• Carrier-number fluctuations in the 2-dimensional electron gas at the LaAlO3/SrTiO3 interface
• Two-Dimensional Electron Gas with High Mobility Forming at BaO/SrTiO3 Interface
• Observation of strontium segregation in LaAlO${}_3$/SrTiO${}_3$ and NdGaO${}_3$/SrTiO${}_3$ oxide heterostructures by X-ray photoemission spectroscopy
• Superconducting tunneling spectroscopy of spin-orbit coupling and orbital depairing in Nb:SrTiO${}_3$
• Transport in strongly-coupled graphene-LaAlO3/SrTiO3 hybrid systems
• Ultrafast Modification of the Polarity at LaAlO${}_3$/SrTiO${}_3$ Interfaces
• Quantum oscillations in an optically-illuminated two-dimensional electron system at the LaAlO${}_3$/SrTiO${}_3$ interface
• Reversible and Persistent Photoconductivity at the NdGaO3/SrTiO3 Conducting Interface
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