Unexpected Anisotropic Two Dimensional Electron Gas at the LaAlO3/SrTiO3 (110) Interface

Abstract

The observation of a two dimensional electron gas (2DEG) (1, 2), superconductivity (3, 4), magnetic effects (5) and electronic phase separation (6-8) at the interfaces of insulating oxides, especially LaAlO3/SrTiO3, has further enhanced the potential of complex oxides for novel electronics. The occurrence of the 2DEG is strongly believed to be driven by the polarization discontinuity (9) at the interface between the two oxides. In this scenario, the crystal orientation plays an important role and no conductivity would be expected for e.g., the interface between LaAlO3 and (110)-oriented SrTiO3, which should not have a polarization discontinuity (10, 11). Here, we report the observation of unexpected conductivity at the LaAlO3/SrTiO3 interface prepared on (110)-oriented SrTiO3. The conductivity was further found to be strongly anisotropic, with the ratio of the conductance along the different directions parallel to the substrate surface showing a remarkable dependence on the oxygen pressure during deposition. The conductance and its anisotropy are discussed based on the atomic structure at the interface, as revealed by Scanning Transmission Electron Microscopy (STEM) and further supported by density functional theory (DFT) calculations.

arXiv comment17 pages, 5 figures

References in corpus (16)

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Cited by in corpus (38)

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• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3(110)
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• Anisotropic two-dimensional electron gas at SrTiO3(110) protected by its native overlayer
• Atomically flat single terminated oxide substrate surfaces
• Orientational tuning of the Fermi sea of confined electrons at the SrTiO3 (110) and (111) surfaces
• Strong correlations elucidate the electronic structure and phase-diagram of LaAlO3/SrTiO3 interface
• The Effect of Polar Fluctuation and Lattice Mismatch on Carrier Mobility at Oxide Interfaces
• Selection rules for Cooper pairing in two-dimensional interfaces and sheets
• Gate Tunable In- and Out-Of-Plane Spin-Orbit Coupling and Spin Splitting Anisotropy at LaAlO3/SrTiO3 (110) Interface
• Strain-induced Defect Superstructure on the SrTiO3(110) Surface
• Two-dimensional electron gas at the PbTiO${}_3$/SrTiO${}_3$ interface: an ab initio study
• Anisotropic effects in two-dimensional materials
• Mechanism, time-reversal symmetry and topology of superconductivity in noncentrosymmetric systems
• Model of two-dimensional electron gas formation at ferroelectric interfaces
• Anisotropic, multi-carrier transport at the (111) LaAlO${}_3$/SrTiO${}_3$ interface
• Origin of interfacial conductivity at complex oxide heterointerfaces: possibility of electron transfer from water chemistry at surface oxygen vacancies
• Thickness Dependent Carrier Density at the Surface of SrTiO3 (111) Slabs
• Vacancy clusters at domain boundaries and band bending at the SrTiO${}_3$(110) surface
• 2D surprises at the surface of 3D materials: confined electron systems in transition metal oxides
• Infrared ellipsometry study of the photo-generated charge carriers at the (001) and (110) surfaces of SrTiO${}_3$ crystals and the interface of corresponding LaAlO${}_3$/SrTiO${}_3$ heterostructures
• Conducting interfaces between amorphous oxide layers and SrTiO3(110) and SrTiO3(111)
• Tunable spin and orbital polarization in SrTiO3-based heterostructures
• Superconductivity at epitaxial LaTiO3-KTaO3 interfaces
• Cation ordering induced polarization enhancement for $PbTi{O}_3$-$SrTi{O}_3$ ferroelectric-dielectric superlattices
• Persistent half-metallic ferromagnetism in a (111)-oriented manganite superlattice
• Reconciling the theoretical and experimental electronic structure of NbO2
• La interstitial defect-induced insulator-metal transition in oxide heterostructures LaAlO3/SrTiO3
• Anisotropy of the infrared-active phonon modes in the mono-domain state of tetragonal SrTiO3 (110)
• Electrostatic tuning of magnetism at the conducting (111) (La${}_{0.3}$Sr${}_{0.7}$)(Al${}_{0.65}$Ta${}_{0.35}$)/SrTiO${}_3$ interface
• 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
• Two-Dimensional Charge Localization at the Perovskite Oxide Interface
• Strong spin-orbit coupling and magnetism in (111) (La${}_{0.3}$Sr${}_{0.7}$)(Al${}_{0.65}$Ta${}_{0.35})$/SrTiO${}_3$
• Room temperature charge-to-spin conversion from q-2DEG at SrTiO3-based interfaces
• First-principles design of ferromagnetic monolayer MnO${}_2$ at the complex interface
• Orbital and Spin Edelstein Effects in KTaO${}_3$(110) Two-Dimensional Electron Gases
• Scanning gate microscopy probing of anisotropic electron flow in a two dimensional electron gas at the (110) ${\mathrm{LaAlO}}_3/{\mathrm{SrTiO}}_3$ interface: A theoretical investigation