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arXiv · 2407.11586

Interface suppressed nematicity and enhanced superconductivity of FeSe/NdFeO3 in the low doping regime

Chihao Li·Yuanhe Song·Xiaoxiao Wang·Minyinan Lei·Xiaoyang Chen·Haichao Xu·Rui Peng·Donglai Feng
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Abstract

The discovery of interface-enhanced superconductivity in single-layer FeSe/oxides has generated intensive research interests. Beyond the family of FeSe interfaced with various TiO$_2$ terminated oxides, high pairing temperature up to 80~K has been recently observed in FeSe interfaced with FeO$_x$-terminated LaFeO$_3$. Here we successfully extend the FeSe/FeO$_x$ superconducting interface to FeSe/NdFeO$_3$, by constructing 1uc-FeSe/6uc-NdFeO$_3$/Nb:SrTiO$_3$ heterostructures. Intriguingly, well-annealed FeSe/NdFeO$_3$ exhibits a low doping level of 0.038$\sim$0.046 ~e$^-/$Fe which deviates universally magic doping level (0.10$\sim$0.12 e$^-/\rm{Fe}$) and provides a new playground for studying the FeSe/oxide interface in the low electron-doped regime. Comparing it with thick FeSe films at the comparable electron doping level induced by surface potassium dosing, FeSe/NdFeO$_3$ shows a larger superconducting gap and the absence of a nematic gap, indicating an enhancement of the superconductivity and suppression of nematicity by the FeSe/FeO$_x$ interface. These results not only expand the FeSe/FeO$_x$ superconducting family but also enrich the current understanding on the roles of the oxide interface.

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Chihao Li, Yuanhe Song, Xiaoxiao Wang, Minyinan Lei, Xiaoyang Chen, Haichao Xu, Rui Peng, Donglai Feng. 2024-07-16. Interface suppressed nematicity and enhanced superconductivity of FeSe/NdFeO3 in the low doping regime. https://doi.org/10.1021/acs.nanolett.4c01493

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