Orientation-dependent electron-phonon coupling in interfacial superconductors LaAlO3/KTaO3

Abstract

The emergent superconductivity at the LaAlO3/KTaO3 interfaces exhibits a mysterious dependence on the KTaO3 crystallographic orientations. Here we show, by soft X-ray angle-resolved photoemission spectroscopy, that the interfacial superconductivity is contributed by mobile electrons with unexpected quasi-three-dimensional character, beyond the "two-dimensional electron gas" scenario in describing oxide interfaces. At differently-oriented interfaces, the quasi-three-dimensional electron gas ubiquitously exists and spatially overlaps with the small q Fuchs-Kliewer surface phonons. Intriguingly, electrons and the Fuchs-Kliewer phonons couple with different strengths depending on the interfacial orientations, and the stronger coupling correlates with the higher superconducting transition temperature. Our results provide a natural explanation for the orientation-dependent superconductivity, and the first evidence that interfacial orientations can affect electron-phonon coupling strength over several nanometers, which may have profound implications for the applications of oxide interfaces in general.

References in corpus (35)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• Unveiling a two-dimensional electron gas with universal subbands at the surface of SrTiO3
• Electronic structure of quantum materials studied by angle-resolved photoemission spectroscopy
• Mapping the Spatial Distribution of Charge Carriers in LaAlO3/SrTiO3 Heterostructures
• Profiling the interface electron gas of LaAlO3/SrTiO3 heterostructures by hard X-ray photoelectron spectroscopy
• Discovery of two-dimensional anisotropic superconductivity at KTaO${}_3$ (111) interfaces
• Two-dimensional superconductivity at the surfaces of KTaO3 gated with ionic liquid
• Phonon-enhanced superconductivity at the FeSe/SrTiO3 interface
• Tailoring the nature and strength of electron-phonon interactions in the SrTiO${}_3$(001) two-dimensional electron liquid
• Subband structure of a two-dimensional electron gas formed at the polar surface of the strong spin-orbit perovskite KTaO${}_3$
• Electric field control of disorder-tunable superconductivity and the emergence of quantum metal at an oxide interface
• Polaronic metal state at the LaAlO3/SrTiO3 interface
• Eliashberg Theory: a short review
• Superconductivity in dilute SrTiO${}_3$: a review
• Observation of two-dimensional superconductivity at the LaAlO3/KTaO3(110) heterointerface
• Phonon mechanism in the most dilute superconductor: n-type SrTiO3
• Phase separation from electron confinement at oxide interfaces
• Tunable superconductivity at the oxide-insulator/KTaO${}_3$ interface and its origin
• A possible mechanism for superconductivity in doped SrTiO3
• Superfluid stiffness of a KTaO3-based two-dimensional electron gas
• Band Structure and Spin-Orbital Texture of the (111)-KTaO3 Two-Dimensional Electron Gas
• Strong energy-momentum dispersion of phonon-dressed carriers in the lightly doped band insulator SrTiO${}_3$
• Electron phonon coupling versus photoelectron energy loss at the origin of replica bands in photoemission of FeSe on SrTiO${}_3$
• Superconductivity at low density near a ferroelectric quantum critical point: doped SrTiO
• Interface superconductivity in LaAlO${}_3$-SrTiO${}_3$ heterostructures
• Electronic phase separation at LaAlO3/SrTiO3 interfaces tunable by oxygen deficiency
• Large polarons as key quasiparticles in SrTiO3 and SrTiO3-based heterostructures
• Theory of superconductivity mediated by Rashba coupling in incipient ferroelectrics
• Bandwidth and Electron Correlation-Tuned Superconductivity in Rb${}_{0.8}$Fe${}_2$(Se${}_{1-z}$S${}_z$)${}_2$
• Electronic and phononic properties of a two dimensional electron gas coupled to dipolar phonons via small-momentum-transfer scattering
• Electronic structure of the BaTi${}_2$As${}_2$O parent compound of the titanium based oxypnictide superconductor
• Gate-tunability of the superconducting state at the $EuO/KTa{O}_3(111)$ interface
• Electronic subbands in the a-LaAlO${}_3$/KTaO${}_3$ interface revealed by quantum oscillations in high magnetic fields
• Hard x-ray angle-resolved photoemission from a buried high-mobility electron system

Cited by in corpus (7)

• Superconducting quantum oscillations and anomalous negative magnetoresistance in a honeycomb nanopatterned oxide interface superconductor
• Unconventional quantum oscillations and evidence of nonparabolic electronic states in quasi-two-dimensional electron system at complex oxide interfaces
• Spin-dependent anisotropic electron-phonon coupling in KTaO${}_3$
• Superconductivity from the Slater mode: Application to KTaO3 heterostructures
• Observation of Quantum-Criticality-Class Crossover at the LaAlO${}_3$/KTaO${}_3$ (111) Interface
• Orientation-dependent superconductivity and electronic structure of the rare-earth metal/KTaO3 interfaces
• Geometric Control of Pairing: Universal Scaling of Superconductivity at KTaO3 Interfaces