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Updated: Jun 14, 2025
Growth and Electrostatic/chemical Properties of Metal/LaAlO3/SrTiO3 Heterostructures
Published on: February 8, 2018
Orientation-dependent electronic structure in interfacial superconductors LaAlO3/KTaO3
Xiaoyang Chen1, Tianlun Yu1, Yuan Liu2
1Advanced Materials Laboratory, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai, China.
Abstract:
Emergent superconductivity at the LaAlO3/KTaO3 interfaces exhibits a mysterious dependence on the KTaO3 crystallographic orientations. Here by soft X-ray angle-resolved photoemission spectroscopy, we directly resolve the electronic structure of the LaAlO3/KTaO3 interfacial superconductors and the non-superconducting counterpart. We find that the mobile electrons that contribute to the interfacial superconductivity show strong k⊥ dispersion. Comparing the superconducting and non-superconducting interfaces, the quasi-three-dimensional electron gas with over 5.5 nm spatial distribution ubiquitously exists and shows similar orbital occupations. The signature of electron-phonon coupling is observed and intriguingly dependent on the interfacial orientations. Remarkably, the stronger electron-phonon coupling signature correlates with the higher superconducting transition temperature. Our observations help scrutinize the theories on the orientation-dependent superconductivity and offer a plausible and straightforward explanation. The interfacial orientation effect that can modify the electron-phonon coupling strength over several nanometers sheds light on the applications of oxide interfaces in general.
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