Origin of two-dimensional electron gases at oxide interfaces: insights from theory

Abstract

The response of oxide thin films to polar discontinuities at interfaces and surfaces has generated an enormous activity due to the variety of interesting effects it gives rise to. A case in point is the discovery of the electron gas at the interface between LaAlO3 and SrTiO3, which has since been shown to be quasi-two-dimensional, switchable, magnetic and/or superconducting. Despite these findings, the origin of the two-dimensional electron gas is highly debated and several possible mechanisms remain. Here we review the main proposed mechanisms and attempt to model expected effects in a quantitative way with the ambition of better constraining what effects can/cannot explain the observed phenomenology. We do it in the framework of a phenomenological model for understanding electronic and/or redox screening of the chemical charge in oxide heterostructures. We also discuss the effect of intermixing, both conserving and non-conserving the total stoichiometry.

34 pages, 9 figures

References in corpus (28)

• Topological Crystalline Insulators
• Magnetic effects at the interface between nonmagnetic oxides
• High Mobility in LaAlO3/SrTiO3 Heterostructures: Origin, Dimensionality and Perspectives
• Metallic and insulating interfaces of amorphous SrTiO3-based oxide heterostructures
• A high-mobility two-dimensional electron gas at the heteroepitaxial spinel/perovskite complex oxide interface of γ-Al2O3/SrTiO3
• Avoiding the polarization catastrophe in LaAlO3 overlayers on SrTiO3(001) through a polar distortion
• A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces
• Polar Discontinuity Doping of the LaVO_3/SrTiO_3 Interface
• LaAlO3 stoichiometry found key to electron liquid formation at LaAlO3/SrTiO3 interfaces
• High mobility conduction at (110) and (111) LaAlO3/SrTiO3 interfaces
• Surface defects and conduction in polar oxide heterostructures
• 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
• Direct k-space mapping of the electronic structure in an oxide-oxide interface
• Topological Classification of Crystalline Insulators with Point Group Symmetry
• Polarity-induced oxygen vacancies at LaAlO3|SrTiO3 interfaces
• Oxide Heterostructures for Efficient Solar Cells
• Unexpected Anisotropic Two Dimensional Electron Gas at the LaAlO3/SrTiO3 (110) Interface
• Controlling the density of the 2DEG at the SrTiO3/LaAlO3 interface
• Hard x-ray photoemission and density functional theory study of the internal electric field in SrTiO3/LaAlO3 oxide heterostructures
• Oxide superlattices with alternating p and n interfaces
• Stoichiometry control of the electronic properties of the LaAlO_3/SrTiO_3 heterointerface
• Fundamental asymmetry in interfacial electronic reconstruction between insulating oxides
• d0 Ferromagnetic Interface Between Non-magnetic Perovskites
• One-dimensional half-metallic interfaces of two-dimensional honeycomb insulators
• Termination control of electronic phases in oxide thin films and interfaces: LaAlO3/SrTiO3(001)
• Evolution of the SrTiO${}_3$ surface electronic state as a function of LaAlO${}_3$ overlayer thickness
• The net charge at interfaces between insulators
• Modulation of electron carrier density at the n-type LaAlO3/SrTiO3 interface by water adsorption

Cited by in corpus (35)

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• Oxide spin-orbitronics: spin-charge interconversion and topological spin textures
• Second-principles method including electron and lattice degrees of freedom
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• Atomically flat single terminated oxide substrate surfaces
• Emergence of one-dimensional wires of free carriers in transition-metal-dichalcogenide nanostructures
• Engineering polar discontinuities in honeycomb lattices
• The Effect of Polar Fluctuation and Lattice Mismatch on Carrier Mobility at Oxide Interfaces
• Two-dimensional electron gas at the PbTiO${}_3$/SrTiO${}_3$ interface: an ab initio study
• Model of two-dimensional electron gas formation at ferroelectric interfaces
• Spin-texture induced by oxygen vacancies in Strontium perovskites (001) surfaces: A theoretical comparison between SrTiO3 and SrHfO3
• Electronic properties of LaAlO3/SrTiO3 n-type interfaces: A GGA+U study
• Elucidating the Influence of Native Defects on Electrical and Optical Properties in Semiconducting Oxides: An Experimental and Theoretical Investigation
• Oxygen vacancies and hydrogen doping in LaAlO3/SrTiO3 heterostructures: electronic properties and impact on surface and interface reconstruction
• Electrostatics and domains in ferroelectric superlattices
• Strain-induced polar discontinuities in two-dimensional materials from combined first-principles and Schrödinger-Poisson simulations
• Ferroelectric control of spin-polarized two-dimensional electron gas
• Influence of the ferroelectric quantum critical point on SrTiO${}_3$ interfaces
• Probing Quantum Confinement and Electronic Structure at Polar Oxide Interfaces
• Temperature-Dependent Band Structure of SrTiO${}_3$ Interfaces
• Possible Flexoelectric Origin of the Lifshitz Transition in LaAlO${}_3$/SrTiO${}_3$ Interfaces
• Metallic interface in non-SrTiO3 based titanate superlattice
• Structural and electronic phenomena at oxyfluoride KTaO${}_3$/K$M$F${}_3$ ($M$ = Zn and Ni) superlattices: Rashba splitting and 2DEG
• Evolution of domain structure with electron doping in ferroelectric thin films
• Electrical permittivity driven metal-insulator transition in heterostructures of nonpolar Mott- and band insulators
• BinPo: An open-source code to compute the band structure of two-dimensional electron systems
• Mechanism for Switchability in Electron-Doped Ferroelectric Interfaces
• Polarity-field driven conductivity in SrTiO${}_3$/LaAlO${}_3$: a hybrid functional study
• Spintronic Quantum Phase Transition in a $Graphene/P{b}_{0.24}S{n}_{0.76}Te$ Heterostructure with Giant Rashba Spin-Orbit Coupling
• Influence of a Realistic Multiorbital Band Structure on Conducting Domain Walls in Perovskite Ferroelectrics
• Magnetotransport in graphene/Pb0.24Sn0.76Te heterostructures: finding a way to avoid catastrophe
• Polarization discontinuity driven two dimensional electron gas at A${}_2$Mo${}_3$O${}_8$/B${}_2$Mo${}_3$O${}_8$ (A, B : Zn,Mg,Cd) interfaces
• Bound States at Semiconductor -- Mott Insulator Interfaces
• Multiferroic interfaces composed of d0 perovskites oxides
• Coupling between tilts and charge carriers at polar-nonpolar perovskite interfaces