Microscopic origin of the mobility enhancement at a spinel/perovskite oxide heterointerface revealed by photoemission spectroscopy

Abstract

The spinel/perovskite heterointerface $\gamma$-Al${}_2$O${}_3$/SrTiO${}_3$ hosts a two-dimensional electron system (2DES) with electron mobilities exceeding those in its all-perovskite counterpart LaAlO${}_3$/SrTiO${}_3$ by more than an order of magnitude despite the abundance of oxygen vacancies which act as electron donors as well as scattering sites. By means of resonant soft x-ray photoemission spectroscopy and \textit{ab initio} calculations we reveal the presence of a sharply localized type of oxygen vacancies at the very interface due to the local breaking of the perovskite symmetry. We explain the extraordinarily high mobilities by reduced scattering resulting from the preferential formation of interfacial oxygen vacancies and spatial separation of the resulting 2DES in deeper SrTiO${}_3$ layers. Our findings comply with transport studies and pave the way towards defect engineering at interfaces of oxides with different crystal structures.

arXiv commentAccepted as Rapid Communications in Physical Review B

References in corpus (24)

• Why Some Interfaces Cannot be Sharp
• The virtual crystal approximation revisited: Application to dielectric and piezoelectric properties of perovskites
• Unveiling a two-dimensional electron gas with universal subbands at the surface of SrTiO3
• Creation and control of a two-dimensional electron liquid at the bare SrTiO3 surface
• A high-mobility two-dimensional electron gas at the heteroepitaxial spinel/perovskite complex oxide interface of γ-Al2O3/SrTiO3
• A polarity-induced defect mechanism for conductivity and magnetism at polar-nonpolar oxide interfaces
• Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures by hard X-ray photoelectron spectroscopy
• Lattice relaxation, electronic screening, and spin and orbital phase diagram of LaTiO${}_3$/SrTiO${}_3$ superlattices
• Tailoring the nature and strength of electron-phonon interactions in the SrTiO${}_3$(001) two-dimensional electron liquid
• Origin of the two-dimensional electron gas at LaAlO3/SrTiO3 interfaces: The role of oxygen vacancies and electronic reconstruction
• Critical thickness for ferromagnetism in LaAlO3/SrTiO3 heterostructures
• High mobility conduction at (110) and (111) LaAlO3/SrTiO3 interfaces
• Polaronic metal state at the LaAlO3/SrTiO3 interface
• Magnetism and superconductivity at LAO/STO-interfaces: the role of Ti 3d interface electrons
• Direct k-space mapping of the electronic structure in an oxide-oxide interface
• Electron Correlation in Oxygen Vacancy in SrTiO${}_3$
• Defect engineering in oxide heterostructures by enhanced oxygen surface exchange
• Control of a two-dimensional electron gas on SrTiO3(111) by atomic oxygen
• Intrinsic Mobility Limiting Mechanisms in Lanthanum-doped Strontium Titanate
• Structure and Correlation Effects in Semiconducting SrTiO${}_3$
• Room temperature formation of high-mobility two-dimensional electron gases at crystalline complex oxide interfaces
• Localized versus itinerant states created by multiple oxygen vacancies in SrTiO3
• Anomalous orbital structure in a spinel-perovskite interface $\gamma$-Al${}_2$O${}_3$/SrTiO${}_3$
• Infrared ellipsometry study of the confined electrons in a high-mobility $\gamma$-Al${}_2$O${}_3$/SrTiO${}_3$ heterostructure

Cited by in corpus (9)

• Magnetic and electronic properties at the gamma-Al2O3/SrTiO3 interface
• Band-Order Anomaly at the γ-Al2O3/SrTiO3 Interface Drives the Electron-Mobility Boost
• Two-Dimensional Electron Gas with High Mobility Forming at BaO/SrTiO3 Interface
• Electron trapping and detrapping in an oxide two-dimensional electron gas: The role of ferroelastic twin walls
• Controlling the electronic interface properties of AlO${}_x$/SrTiO${}_3$ heterostructures
• Enhancement of electron mobility at oxide interfaces induced by WO3 overlayers
• Quantum oscillations in an optically-illuminated two-dimensional electron system at the LaAlO${}_3$/SrTiO${}_3$ interface
• High stability 2D electron gases formed in Si3N4/Al//KTaO3 heterostructures: synthesis and in-depth interfacial characterization
• High-mobility two-dimensional electron gas in $\gamma$-Al${}_2$O${}_3$/SrTiO${}_3$ heterostructures