Nodeless superconducting gap and electron-boson coupling in (La,Pr,Sm) <sub>3</sub> Ni <sub>2</sub> O <sub>7</sub> films
Abstract
The discovery of superconductivity in Ruddlesden-Popper bilayer nickelate films under ambient pressure provides an opportunity to directly investigate electronic energy scales of the superconducting state and the pairing mechanism. We report angle-resolved photoemission spectroscopy measurements of superconducting (La,Pr,Sm) 3 Ni 2 O 7 thin films by developing an ultrahigh-vacuum cryogenic sample quenching and transfer technique. A superconducting gap of ~18 milli–electron volts with coherence peaks is observed along the Brillouin zone diagonal. The finite gap persists across the entire Brillouin zone, revealing the absence of gap nodes. A kink is observed in the energy-momentum dispersion at ~70 milli–electron volts below the Fermi level, indicating an electron-boson coupling. The simultaneous observation of a nodeless superconducting gap and electron-boson coupling provides insight into the pairing symmetry and gluing mechanism in Ruddlesden-Popper bilayer nickelates.
Article Details
Journal Info
Science
American Association for the Advancement of Science
Authors (21)
Jianchang Shen
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Guangdi Zhou
Yu Miao
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Peng Li
Zhipeng Ou
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Yaqi Chen
Zechao Wang
State Key Laboratory of Quantum Functional Materials, Department of Physics, Guangdong Provincial Key Laboratory of Topological Matter, and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology, Shenzhen, China.
Runqing Luan
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Hongxu Sun
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Zikun Feng
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Xinru Yong
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Yueying Li
Lizhi Xu
Wei Lv
Zihao Nie
Heng Wang
Haoliang Huang
Yu-Jie Sun
Qi-Kun Xue
Junfeng He
Department of Physics, University of Science and Technology of China, Hefei, Anhui, China.
Zhuoyu Chen