Orientation-dependent electronic structure in interfacial superconductors LaAlO<sub>3</sub>/KTaO<sub>3</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39231978.
- Also identified by DOI 10.1038/s41467-024-51969-4 and PMC identifier 11374786.
- Licence recorded as CC BY-NC-ND.
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Abstract
Emergent superconductivity at the LaAlO<sub>3</sub>/KTaO<sub>3</sub> interfaces exhibits a mysterious dependence on the KTaO<sub>3</sub> crystallographic orientations. Here by soft X-ray angle-resolved photoemission spectroscopy, we directly resolve the electronic structure of the LaAlO<sub>3</sub>/KTaO<sub>3</sub> interfacial superconductors and the non-superconducting counterpart. We find that the mobile electrons that contribute to the interfacial superconductivity show strong k<sub>⊥</sub> 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.