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.

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Cited by in corpus (7)

• Anisotropic effects in two-dimensional materials
• 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