Anisotropic Electronic Structure of the Two-Dimensional Electron Gas at the AlOx/KTaO3(110) interface

Abstract

Oxide-based two-dimensional electron gases (2DEGs) have generated significant interest due to their potential for discovering novel physical properties. Among these, 2DEGs formed in KTaO3 stand out due to the recently discovered crystal face-dependent superconductivity and large Rashba splitting, both of which hold potential for future oxide electronics devices. In this work, angle-resolved photoemission spectroscopy is used to study the electronic structure of the 2DEG formed at the (110) surface of KTaO3 after deposition of a thin Al layer. Our experiments revealed a remarkable anisotropy in the orbital character of the electron-like dispersive bands, which form a Fermi surface consisting of two elliptical contours with their major axes perpendicular to each other. The measured electronic structure is used to constrain the modeling parameters of self-consistent tight-binding slab calculations of the band structure. In these calculations, an anisotropic Rashba splitting is found with a value as large as 4 meV at the Fermi level along the [-110] crystallographic direction. This large unconventional and anisotropic Rashba splitting is rationalized based on the orbital angular momentum formulation. These findings provide insights into the interpretation of spin-orbitronics experiments and help to constrain models for superconductivity in the KTO(110)-2DEG system.

References in corpus (33)

• Maximally localized Wannier functions: Theory and applications
• 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
• Probing the Low-Energy Electronic Structure of Complex Systems by ARPES
• Tunable polaronic conduction in anatase TiO2
• Discovery of two-dimensional anisotropic superconductivity at KTaO${}_3$ (111) interfaces
• Two-dimensional superconductivity at the surfaces of KTaO3 gated with ionic liquid
• Orbital-Angular-Momentum Based Origin of Rashba-Type Surface Band Splitting
• Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO${}_3$
• High mobility conduction at (110) and (111) LaAlO3/SrTiO3 interfaces
• Quasiparticle dynamics and spin-orbital texture of the SrTiO3 two-dimensional electron gas
• Universal Fabrication of Two-Dimensional Electron Systems in Functional Oxides
• Observation of two-dimensional superconductivity at the LaAlO3/KTaO3(110) heterointerface
• Anisotropic two-dimensional electron gas at SrTiO3(110) protected by its native overlayer
• Control of a two-dimensional electron gas on SrTiO3(111) by atomic oxygen
• Mixed Dimensionality of Confined Conducting Electrons in the Surface Region of SrTiO${}_3$
• Spin and Orbital Angular Momentum Structures of Cu(111) and Au(111) Surface States
• Orientational tuning of the Fermi sea of confined electrons at the SrTiO3 (110) and (111) surfaces
• Spin-charge interconversion in KTaO${}_3$ two-dimensional electron gases
• Tunable superconductivity at the oxide-insulator/KTaO${}_3$ interface and its origin
• Band Structure and Spin-Orbital Texture of the (111)-KTaO3 Two-Dimensional Electron Gas
• Direct visualization of Rashba-split bands and spin/orbital-charge interconversion at KTaO${}_3$ interfaces
• Nature of Orbital and Spin Rashba Coupling in the Surface Bands of SrTiO3 and KTaO3
• Absence of Giant Spin Splitting in the Two-Dimensional Electron Liquid at the Surface of SrTiO${}_3$ (001)
• Atomically precise lateral modulation of a two-dimensional electron liquid in anatase TiO2 thin films
• Observation of a two-dimensional electron gas at CaTiO${}_3$ film surfaces
• Tunable two-dimensional electron system at the (110) surface of SnO${}_2$
• Experimental Evidence of t2g Electron-Gas Rashba Interaction Induced by Asymmetric Orbital Hybridization
• Gate-tunable superconductivity at SrTiO3 surface realized by Al layer evaporation
• Controlling the electronic interface properties of AlO${}_x$/SrTiO${}_3$ heterostructures
• $d_{xz/yz}$ Orbital Subband Structures and Chiral Orbital Angular Momentum in the (001) Surface States of SrTiO${}_3$
• A Laser-ARPES View of the 2D Electron Systems at LaAlO3/SrTiO3 and Al/SrTiO3 Interfaces
• BinPo: An open-source code to compute the band structure of two-dimensional electron systems

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• High stability 2D electron gases formed in Si3N4/Al//KTaO3 heterostructures: synthesis and in-depth interfacial characterization
• Violation of Pauli Limit at KTaO3(110) Interfaces
• 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
• Controlling Spin-Mixing Conductance in KTaO${}_3$ 2DEGs by Varying Argon-Ion Irradiation Time
• Orientation-dependent superconductivity and electronic structure of the rare-earth metal/KTaO3 interfaces