Particle-hole mixed Bogoliubov quasiparticles and Cooper instability in single-unit-cell FeSe/SrTiO3 films

Zhiyuan Wei; Shaozhi Li; Bo Liu; Xiupeng Sun; Yinqi Hu; Shuai Sun; Shuting Peng; Yang Luo; Linwei Huai; Jianchang Shen; Bingqian Wang; Yu Miao; Zhipeng Ou; Yao Wang; Kun Jiang; Junfeng He

doi:10.1038/s43246-024-00554-9

Communications Materials (Jul 2024)

Particle-hole mixed Bogoliubov quasiparticles and Cooper instability in single-unit-cell FeSe/SrTiO3 films

Zhiyuan Wei,
Shaozhi Li,
Bo Liu,
Xiupeng Sun,
Yinqi Hu,
Shuai Sun,
Shuting Peng,
Yang Luo,
Linwei Huai,
Jianchang Shen,
Bingqian Wang,
Yu Miao,
Zhipeng Ou,
Yao Wang,
Kun Jiang,
Junfeng He

Affiliations

Zhiyuan Wei: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Shaozhi Li: Department of Physics and Astronomy, Clemson University
Bo Liu: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Xiupeng Sun: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Yinqi Hu: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Shuai Sun: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Shuting Peng: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Yang Luo: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Linwei Huai: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Jianchang Shen: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Bingqian Wang: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Yu Miao: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Zhipeng Ou: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China
Yao Wang: Department of Physics and Astronomy, Clemson University
Kun Jiang: Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences
Junfeng He: Department of Physics and CAS Key Laboratory of Strongly-coupled Quantum Matter Physics, University of Science and Technology of China

DOI: https://doi.org/10.1038/s43246-024-00554-9
Journal volume & issue: Vol. 5, no. 1
pp. 1 – 6

Abstract

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Abstract In conventional superconductors, Bogoliubov quasiparticles and Cooper instability provide a paradigm to describe the superconducting state and the superconducting transition, respectively. However, whether these concepts can be adapted to describe Fe-based superconductors requires rigorous examinations from experiments. Here, we report angle-resolved photoemission studies on single-layer FeSe films grown on SrTiO3 substrate. Due to the improved clarity, our results reveal both particle and hole branches of the energy band with clear quasiparticles. The dispersion and coherence factors are extracted, which unveil the particle-hole mixed Bogoliubov quasiparticles in the superconducting state of the FeSe/STO films. Effective pairing susceptibility is also deduced as a function of temperature, which indicates the persistence of Cooper instability in Fe-based superconductors.

Published in Communications Materials

ISSN: 2662-4443 (Online)
Publisher: Nature Portfolio
Country of publisher: United States
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.nature.com/commsmat/

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