Orientation-dependent superconductivity and electronic structure of the rare-earth metal/KTaO3 interfaces

Guowei Yang; Weifan Zhu; Jiawen Zhang; Hao Zheng; Yi Wu; Huali Zhang; Ge Ye; Dajun Su; Yanan Zhang; Chao Cao; Xin Lu; Huiqiu Yuan; Yang Liu

doi:10.1088/1361-648x/add2bf

arXiv · 2311.09588

Orientation-dependent superconductivity and electronic structure of the rare-earth metal/KTaO3 interfaces

Guowei Yang·Weifan Zhu·Jiawen Zhang·Hao Zheng·Yi Wu·Huali Zhang·Ge Ye·Dajun Su·Yanan Zhang·Chao Cao·Xin Lu·Huiqiu Yuan·Yang Liu

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Abstract

The recent discovery of orientation-dependent superconductivity in KTaO3-based interfaces has attracted considerable interest, while the underlying origin remains an open question. Here we report a different approach to tune the interfacial electron gas and superconductivity by forming interfaces between rare-earth (RE) metals (RE being La, Ce, Eu) and KTaO3 substrates with different orientations. We found that the interfacial superconductivity is strongest for the Eu/KTaO3 interfaces, becomes weaker in La/KTaO3 and is absent in Ce/KTaO3. Using in-situ photoemission, we observed distinct valence bands associated with RE metals, as well as a pronounced orientation dependence in the interfacial electronic structure, which can be linked to the orientation-dependent superconductivity. The photoemission spectra show similar double-peak structures for the (111) and (110) oriented interfaces, with an energy separation close to the LO4 phonon of KTaO3. Detailed analyses suggest that this double-peak structure could be attributed to electron-phonon coupling, which might be important for the interfacial superconductivity.

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Guowei Yang, Weifan Zhu, Jiawen Zhang, Hao Zheng, Yi Wu, Huali Zhang, Ge Ye, Dajun Su, Yanan Zhang, Chao Cao, Xin Lu, Huiqiu Yuan, Yang Liu. 2023-11-16. Orientation-dependent superconductivity and electronic structure of the rare-earth metal/KTaO3 interfaces. https://doi.org/10.1088/1361-648x/add2bf

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