Interface-Suppressed Nematicity and Enhanced Superconducting Pairing Strength of FeSe/NdFeO3 in the Low-Doping Regime

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

doi:10.1021/acs.nanolett.4c01493

Interface-Suppressed Nematicity and Enhanced Superconducting Pairing Strength of FeSe/NdFeO₃ in the Low-Doping Regime

Nano Lett. 2024 Jul 10;24(27):8303-8310. doi: 10.1021/acs.nanolett.4c01493. Epub 2024 Jun 27.

Authors

Chihao Li¹, Yuanhe Song¹, Xiaoxiao Wang¹, Minyinan Lei¹, Xiaoyang Chen¹, Haichao Xu^{1

2}, Rui Peng^{1

2}, Donglai Feng^{1

3

4

5}

Affiliations

¹ Laboratory of Advanced Materials, State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China.
² Shanghai Research Center for Quantum Sciences, Shanghai 201315, China.
³ National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230026, China.
⁴ New Cornerstone Science Laboratory, University of Science and Technology of China, Hefei 230026, China.
⁵ Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.

PMID: 38934420
DOI: 10.1021/acs.nanolett.4c01493

Abstract

The discovery of interfacial superconductivity in monolayer FeSe/oxides has spurred intensive research interest. Here we not only extend the FeSe/FeO_x superconducting interface to FeSe/NdFeO₃ but also establish robust interface-enhanced superconductivity at a very low doping level. Specifically, well-annealed FeSe/NdFeO₃ exhibits a low doping level of 0.038-0.046 e^-/Fe with a larger superconducting pairing gap without a nematic gap, indicating an enhancement of the enhanced superconducting pairing strength and suppression of nematicity by the FeSe/FeO_x interface compared with those of thick FeSe films. These results improve our understanding of the roles of the oxide interface in the low-electron-doped regime.

Keywords: FeSe; FeSe/oxide interface; low-doping regime; superconductivity.