Surface defects and conduction in polar oxide heterostructures

Abstract

The polar interface between LaAlO${}_3$ and SrTiO${}_3$ has shown promise as a field effect transistor, with reduced (nanoscale) feature sizes and potentially added functionality over conventional semiconductor systems. However, the mobility of the interfacial two-dimensional electron gas (2DEG) is lower than desirable. Therefore to progress, the highly debated origin of the 2DEG must be understood. Here we present a case for surface redox reactions as the origin of the 2DEG, in particular surface O vacancies, using a model supported by first principles calculations that describes the redox formation. In agreement with recent spectroscopic and transport measurements, we predict a stabilization of such redox processes (and hence Ti 3$d$ occupation) with film thickness beyond a critical value, which can be smaller than the critical thickness for 2D electronic conduction, since the surface defects generate trapping potentials that will affect the interface electron mobility. Several other recent experimental results, such as lack of core level broadening and shifts, find natural explanation. Pristine systems will likely require changed growth conditions or modified materials with a higher vacancy free energy.

Revised version

References in corpus (13)

• Why Some Interfaces Cannot be Sharp
• 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
• Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures by hard X-ray photoelectron spectroscopy
• Origin of Metallic States at Heterointerface between Band Insulators LaAlO${}_3$ and SrTiO${}_3$
• Evolution of the interfacial structure of LaAlO3 on SrTiO3
• Polarity-induced oxygen vacancies at LaAlO3|SrTiO3 interfaces
• Charge writing at the LaAlO3/SrTiO3 surface
• Dynamical response and confinement of the electrons at the LaAlO3/SrTiO3 interface
• Berry-phase theory of polar discontinuities at oxide-oxide interfaces
• Oxide superlattices with alternating p and n interfaces
• The net charge at interfaces between insulators

Cited by in corpus (49)

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• Controlling the density of the 2DEG at the SrTiO3/LaAlO3 interface
• Electron Accumulation and Emergent Magnetism in LaMnO3/SrTiO3 Heterostructures
• Doping-dependent band structure of LaAlO${}_3$/SrTiO${}_3$ interfaces by soft x-ray polarization-controlled resonant angle-resolved photoemission
• Quantum-Matter Heterostructures
• Hard x-ray photoemission and density functional theory study of the internal electric field in SrTiO3/LaAlO3 oxide heterostructures
• Electronic charges and electric potential at LaAlO3/SrTiO3 interfaces studied by core-level photoemission spectroscopy
• Tuning the two-dimensional electron gas at the LaAlO3/SrTiO3(001) interface by metallic contacts
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• Localized versus itinerant states created by multiple oxygen vacancies in SrTiO3
• Atomic layer engineering of perovskite oxides for chemically sharp heterointerfaces
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• Polarity induced electronic and atomic reconstruction at NdNiO2/SrTiO3 interfaces
• Electrochemical ferroelectric switching: The origin of polarization reversal in ultrathin films
• 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
• Band inversion driven by electronic correlations at the (111) LaAlO${}_3$/SrTiO${}_3$ interface
• Charge compensation at the interface between the polar NaCl(111) surface and a NaCl aqueous solution
• Electronic phase separation at LaAlO3/SrTiO3 interfaces tunable by oxygen deficiency
• Origin of interfacial conductivity at complex oxide heterointerfaces: possibility of electron transfer from water chemistry at surface oxygen vacancies
• Termination control of electronic phases in oxide thin films and interfaces: LaAlO3/SrTiO3(001)
• Proposal of a one-dimensional electron gas in the steps at the LaAlO${}_3$-SrTiO${}_3$ interface
• Superstripes and complexity in high-temperature superconductors
• First-Principles Modeling of Pt/LaAlO3/SrTiO3 Capacitors Under an External Bias Potential
• 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
• Characteristic Lengths of Interlayer Charge-Transfer in Correlated Oxide Heterostructures
• Nanoscale control of the metal-insulator transition at LAO/KTO (110) and LAO/KTO (111) interfaces
• Emergent Magnetic Phenomenon with Unconventional Structure in Epitaxial Manganate Thin Films
• Probing Quantum Confinement and Electronic Structure at Polar Oxide Interfaces
• Lattice screening of the polar catastrophe and hidden in-plane polarization in KNbO${}_3$/BaTiO${}_3$ interfaces
• Enhancement of electron mobility at oxide interfaces induced by WO3 overlayers
• La interstitial defect-induced insulator-metal transition in oxide heterostructures LaAlO3/SrTiO3
• 2D Surface Phase Diagram of a Multicomponent Perovskite Oxide: La${}_{0.8}$Sr${}_{0.2}$MnO${}_3$(110)
• Improvement in the Performance and Efficiency on Self-Deficient CaTiO${}_3$: Towards Sustainable and Affordable New-Generation Solar Cells
• Strain-controlled Insulator-Metal Transition in YTiO3/SrTiO3 Superlattices: A First-Principles Study
• Influence of gas ambient on charge writing at the LaAlO3/SrTiO3 heterointerface
• Hard X-ray photoemission spectroscopy of LaVO${}_3$/SrTiO${}_3$: Band alignment and electronic reconstruction
• In situ investigation of conducting interface formation in LaAlO3/SrTiO3 heterostructure
• Polarity-field driven conductivity in SrTiO${}_3$/LaAlO${}_3$: a hybrid functional study
• Large electropositive cations as surfactants for the growth of polar epitaxial films
• Reconfigurable Oxide Nanoelectronics by Tip-induced Electron Delocalization
• Coupling between tilts and charge carriers at polar-nonpolar perovskite interfaces
• High-quality Nano-patterning of Oxide Interfaces Using Transferred Gold Mask