Direct k-space mapping of the electronic structure in an oxide-oxide interface

Abstract

The interface between LaAlO3 and SrTiO3 hosts a two-dimensional electron system of itinerant carriers, although both oxides are band insulators. Interface ferromagnetism coexisting with superconductivity has been found and attributed to local moments. Experimentally, it has been established that Ti 3d electrons are confined to the interface. Using soft x-ray angle-resolved resonant photoelectron spectroscopy we have directly mapped the interface states in k-space. Our data demonstrate a charge dichotomy. A mobile fraction contributes to Fermi surface sheets, whereas a localized portion at higher binding energies is tentatively attributed to electrons trapped by O-vacancies in the SrTiO3. While photovoltage effects in the polar LaAlO3 layers cannot be excluded, the apparent absence of surface-related Fermi surface sheets could also be fully reconciled in a recently proposed electronic reconstruction picture where the built-in potential in the LaAlO3 is compensated by surface O-vacancies serving also as charge reservoir.

8 pages, 6 figures, incl. Supplemental Information

References in corpus (8)

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• Magnetic effects at the interface between nonmagnetic oxides
• Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping
• Avoiding the polarization catastrophe in LaAlO3 overlayers on SrTiO3(001) through a polar distortion
• Surface defects and conduction in polar oxide heterostructures
• Polarity-induced oxygen vacancies at LaAlO3|SrTiO3 interfaces
• Oxygen vacancies at titanate interfaces: two-dimensional magnetism and orbital reconstruction
• Coherent and Incoherent States of Electron-doped SrTiO3

Cited by in corpus (55)

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• Origin of two-dimensional electron gases at oxide interfaces: insights from theory
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• Doping-dependent band structure of LaAlO${}_3$/SrTiO${}_3$ interfaces by soft x-ray polarization-controlled resonant angle-resolved photoemission
• Mechanisms of charge transfer and redistribution in LaAlO3/SrTiO3 revealed by high-energy optical conductivity
• Quantum-Matter Heterostructures
• Energetic, spatial and momentum character of a buried interface: the two-dimensional electron gas between two metal oxides
• Persistent photoconductivity in 2-dimensional electron gases at different oxide interfaces
• Competition between electron pairing and phase coherence in superconducting interfaces
• Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy
• Emerging magnetism and electronic phase separation at titanate interfaces
• Electron-phonon Coupling and the Superconducting Phase Diagram of the LaAlO3-SrTiO3 Interface
• Electron correlation and magnetism at the LaAlO${}_3$/SrTiO${}_3$ interface: A DFT+DMFT investigation
• Photoresponse dynamics in amorphous-LaAlO${}_3$/SrTiO${}_3$ interfaces
• Tuning the two-dimensional electron liquid at oxide interfaces by buffer-layer-engineered redox reactions
• Electronic phase separation at LaAlO3/SrTiO3 interfaces tunable by oxygen deficiency
• Symmetry and correlation effects on band structure explain the anomalous transport properties of (111) LaAlO${}_3$/SrTiO${}_3$
• Interface exchange processes in LaAlO${}_3$/SrTiO${}_3$ induced by oxygen vacancies
• Evolution of the SrTiO${}_3$ surface electronic state as a function of LaAlO${}_3$ overlayer thickness
• Symmetry breaking at the (111) interfaces of SrTiO${}_3$ hosting a 2D-electron system
• Thermally excited multi-band conduction in LaAlO3/SrTiO3 heterostructures exhibiting magnetic scattering
• Oxygen vacancies and hydrogen doping in LaAlO3/SrTiO3 heterostructures: electronic properties and impact on surface and interface reconstruction
• 2D surprises at the surface of 3D materials: confined electron systems in transition metal oxides
• Formation and observation of a quasi-two-dimensional $d_{xy}$ electron liquid in epitaxially stabilized Sr${}_{2-x}$La${}_x$TiO${}_4$ thin films
• Dimensionality-tuned electronic structure of nickelate superlattices explored by soft-x-ray angle resolved photoelectron spectroscopy
• Raman and fluorescence contributions to resonant inelastic soft x-ray scattering on LaAlO${}_3$/SrTiO${}_3$ heterostructures
• The mechanism of spin-orbit coupling in a 2D oxide interface
• Carrier-number fluctuations in the 2-dimensional electron gas at the LaAlO3/SrTiO3 interface
• Probing Quantum Confinement and Electronic Structure at Polar Oxide Interfaces
• Hydrostatic pressure response of an oxide two-dimensional electron system
• Controlling the electronic interface properties of AlO${}_x$/SrTiO${}_3$ heterostructures
• Electronic structure of SrTi${}_{1-x}$V${}_x$O${}_3$ films studied by $insitu$ photoemission spectroscopy: Screening for a transparent electrode material
• Two-dimensional electron systems in perovskite oxide heterostructures: Role of the polarity-induced substitutional defects
• Temperature-Dependent Band Structure of SrTiO${}_3$ Interfaces
• Ballistic transport through quantum point contacts of multi-orbital oxides
• Strong interplay between electron-phonon interaction and disorder in low doped systems
• Electronic band structure of Ti2O3 thin films studied by angle-resolved photoemission spectroscopy
• $d_{xz/yz}$ Orbital Subband Structures and Chiral Orbital Angular Momentum in the (001) Surface States of SrTiO${}_3$
• La interstitial defect-induced insulator-metal transition in oxide heterostructures LaAlO3/SrTiO3
• Multi-orbital Fulde-Ferrell-Larkin-Ovchinnikov State in SrTiO_3 Heterostructures
• A Laser-ARPES View of the 2D Electron Systems at LaAlO3/SrTiO3 and Al/SrTiO3 Interfaces
• Hard X-ray photoemission spectroscopy of LaVO${}_3$/SrTiO${}_3$: Band alignment and electronic reconstruction
• Electrical permittivity driven metal-insulator transition in heterostructures of nonpolar Mott- and band insulators
• Emergent phenomena at oxide interfaces studied with standing-wave photoelectron spectroscopy
• Ultrafast X-ray Absorption Spectroscopy of Strongly Correlated Systems: Core Hole Effect
• Oxide Heterostructures from a Realistic Many-Body Perspective
• Polarity-field driven conductivity in SrTiO${}_3$/LaAlO${}_3$: a hybrid functional study
• Resolving interfacial charge transfer in titanate superlattices using resonant X-ray reflectometry
• Quantized conductance in a one-dimensional ballistic oxide nanodevice
• Probing the polar-nonpolar oxide interfaces using resonant x-ray standing wave techniques
• Three-dimensionality of mobile electrons at X-ray-irradiated LaAlO${}_3$/SrTiO${}_3$ interfaces
• Extreme mobility enhancement of two-dimensional electron gases at oxide interfaces via charge transfer induced modulation doping