A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces

Abstract

The discovery of conducting two-dimensional electron gas (2DEG) and magnetism at the interface between insulating nonmagnetic oxides, as exemplified by the polar LaAlO3 and nonpolar SrTiO3 has raised prospects for attaining interfacial functionalities absent in the component materials. Yet, the microscopic origin of such emergent phenomena remains unclear, posing obstacles to design of improved functionalities. Using first principles defect calculations, we reveal a unifying polarity-induced defect mechanism for both conductivity and magnetism at polar-nonpolar interfaces of nonmagnetic insulating oxides. We demonstrate that the polar-discontinuity across the interface triggers thermodynamically the spontaneous formation of certain defects that in turn cancel the polar field induced by the polar discontinuity. It turns out that the 2DEG originates from those spontaneously formed surface donor defects (oxygen vacancy), but the density of 2DEG is controlled by the interfacial anti-site acceptor defects (Al-on-Ti). The interface magnetism is found to originate from the un-ionized deep Ti-on-Al anti-site donor defects within the LaAlO3 side near the interface. Our results suggest practical design guidelines for inducing and controlling both 2DEG and magnetism at polar-nonpolar oxide interfaces.

arXiv comment20 pages, 6 figures and 1 table

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• Oxide spin-orbitronics: spin-charge interconversion and topological spin textures
• Origin of two-dimensional electron gases at oxide interfaces: insights from theory
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• Room Temperature Giant Charge-to-Spin Conversion at SrTiO3/LaAlO3 Oxide Interface
• Creation of high mobility two-dimensional electron gases via strain induced polarization at an otherwise nonpolar complex oxide interface
• Electron Accumulation and Emergent Magnetism in LaMnO3/SrTiO3 Heterostructures
• Fundamental difference in the electronic reconstruction of infinite-layer vs. perovskite neodymium nickelate films on SrTiO${}_3$(001)
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• Charge transfer driven emergent phenomena in oxide heterostructures
• Emergent nanoscale superparamagnetism at oxide interfaces
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• Itinerant ferromagnetism of the Pd-terminated polar surface of PdCoO${}_2$
• Gate-tunable band structure of the LaAlO${}_3$-SrTiO${}_3$ interface
• Localized versus itinerant states created by multiple oxygen vacancies in SrTiO3
• Creating Two-Dimensional Electron Gas in Nonpolar Oxide Interface via Polarization Discontinuity: First-Principles Analysis of CaZrO3/SrTiO3 Heterostructure
• The Effect of Polar Fluctuation and Lattice Mismatch on Carrier Mobility at Oxide Interfaces
• Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy
• Controlling Kondo-like Scattering at the SrTiO3-based Interfaces
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• Oxygen Electromigration and Energy Band Reconstruction Induced by Electrolyte Field Effect at Oxide Interfaces
• Defect Modulation Doping
• Tuning up or down the critical thickness in LaAlO3/SrTiO3 through in situ deposition of metal overlayers
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• Model of two-dimensional electron gas formation at ferroelectric interfaces
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• A switchable two-dimensional electron gas based on ferroelectric Ca:SrTiO${}_3$
• Tuning the two-dimensional electron liquid at oxide interfaces by buffer-layer-engineered redox reactions
• Aperiodic quantum oscillations in the two-dimensional electron gas at the LaAlO3/SrTiO3 interface
• Origin of interfacial conductivity at complex oxide heterointerfaces: possibility of electron transfer from water chemistry at surface oxygen vacancies
• Interface exchange processes in LaAlO${}_3$/SrTiO${}_3$ induced by oxygen vacancies
• Antisite defects at oxide interfaces
• Electronic Structure of Oxide Interfaces: A Comparative Analysis of GdTiO${}_3$/SrTiO${}_3$ and LaAlO${}_3$/SrTiO${}_3$ Interfaces
• Oxygen vacancies and hydrogen doping in LaAlO3/SrTiO3 heterostructures: electronic properties and impact on surface and interface reconstruction
• Characteristic Lengths of Interlayer Charge-Transfer in Correlated Oxide Heterostructures
• Raman and fluorescence contributions to resonant inelastic soft x-ray scattering on LaAlO${}_3$/SrTiO${}_3$ heterostructures
• Stoichiometry Dependence of Potential Screening at La${}_{(1-\delta )}$Al${}_{(1+\delta )}$O${}_3$/SrTiO${}_3$ Interfaces
• Emergent Magnetic Phenomenon with Unconventional Structure in Epitaxial Manganate Thin Films
• Tunable Rashba spin-orbit coupling and its interplay with multiorbital effect and magnetic ordering at oxide interfaces
• Tuning the Electronic Properties of LAO/STO Interfaces by Irradiating LAO Surface with Low-Energy Cluster Ion Beams
• Probing Quantum Confinement and Electronic Structure at Polar Oxide Interfaces
• Influence of the ferroelectric quantum critical point on SrTiO${}_3$ interfaces
• Hydrostatic pressure response of an oxide two-dimensional electron system
• Unexpected Termination Switching and Polarity Compensation in LaAlO3/SrTiO3 heterostructures
• Band offsets at amorphous-crystalline $A{l}_2{O}_3-SrTi{O}_3$ oxide interfaces
• Ferroelectric-HfO2/Oxide Interfaces, Oxygen Distribution Effect and Implications for Device Performance
• Observation of transient superconductivity at the LaAlO${}_3$/SrTiO${}_3$ interface
• Two-dimensional electron systems in perovskite oxide heterostructures: Role of the polarity-induced substitutional defects
• Density inhomogeneities and Rashba spin-orbit coupling interplay in oxide interfaces
• Strain-driven sign interchange of surface two-dimensional electron and hole gases in KTaO3 thin film
• Enhancement of electron mobility at oxide interfaces induced by WO3 overlayers
• Anomalous conductivity, Hall factor, magnetoresistance, and thermopower of accumulation layer in ${\text{SrTiO}}_3$
• Superconductivity in epitaxially grown LaVO3/KTaO3(111) heterostructures
• La interstitial defect-induced insulator-metal transition in oxide heterostructures LaAlO3/SrTiO3
• Analysis of electronic and structural properties of surfaces and interfaces based on LaAlO3 and SrTiO3
• Surface and interface effects in oxygen deficient SrMnO${}_3$ thin films grown on SrTiO${}_3$
• Torque magnetometry of an amorphous-alumina/strontium-titanate interface
• Hard X-ray photoemission spectroscopy of LaVO${}_3$/SrTiO${}_3$: Band alignment and electronic reconstruction
• Inhomogeneous superconductivity and quasilinear magnetoresistance at amorphous LaTiO3/SrTiO3 interfaces
• Direct observation of two-dimensional small polarons at correlated oxide interface
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• Solution Monolayer Epitaxy for Tunable Atomically Sharp Oxide Interfaces
• Interplay between density and superconducting quantum critical fluctuations
• In situ investigation of conducting interface formation in LaAlO3/SrTiO3 heterostructure
• Polarity-field driven conductivity in SrTiO${}_3$/LaAlO${}_3$: a hybrid functional study
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• Interfacial reconstruction effects in insulating double perovskite Nd${}_2$NiMnO${}_6$/SrTiO${}_3$ and Nd${}_2$NiMnO${}_6$/NdGaO${}_3$ thin films
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• Large electropositive cations as surfactants for the growth of polar epitaxial films
• Probing the polar-nonpolar oxide interfaces using resonant x-ray standing wave techniques
• Many-body description of two-dimensional van der Waals ferroelectric $\alpha -$In${}_2$Se${}_3$
• Superfluid response of two-dimensional filamentary superconductors
• Coupling between tilts and charge carriers at polar-nonpolar perovskite interfaces