Localized vs. delocalized character of charge carriers in LaAlO3/ SrTiO3 superlattices

Abstract

Understanding the nature of electrical conductivity, superconductivity and magnetism between layers of oxides is of immense importance for the design of electronic devices employing oxide heterostructures. We demonstrate that resonant inelastic X-ray scattering can be applied to directly probe the carriers in oxide heterostructures. Our investigation on epitaxially grown LaAlO3/SrTiO3 superlattices unambiguously reveals the presence of both localized and delocalized Ti 3d carriers. These two types of carriers are caused by oxygen vacancies and electron transfer due to the polar discontinuity at the interface. This result allows explaining the reported discrepancy between theoretically calculated and experimentally measured carrier density values in LaAlO3/SrTiO3 heterostructures.

14 pages, 3 figures

References in corpus (13)

• Magnetic effects at the interface between nonmagnetic oxides
• Why Some Interfaces Cannot be Sharp
• Electric Field Control of the LaAlO${}_3$/SrTiO${}_3$ Interface Ground State
• The role of oxygen vacancies in SrTiO3 at the LaAlO3/SrTiO3 interface
• High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Orbital reconstruction and two-dimensional electron gas at the LaAlO3/SrTiO3 interface
• Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures by hard X-ray photoelectron spectroscopy
• Polar catastrophe and electronic reconstructions at the LaAlO3/SrTiO3 interface: evidence from optical second harmonic generation
• Multiple conducting carriers generated in LaAlO3/SrTiO3 heterostructures
• Oxide superlattices with alternating p and n interfaces
• Electronic structure of the SrTiO${}_3$/LaAlO${}_3$ interface revealed by resonant soft x-ray scattering
• Resonant soft x-ray scattering from stepped surfaces of SrTiO3

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