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arXiv · 2105.12394

Revealing the Heavy Quasiparticles in the Heavy-Fermion Superconductor CeCu2Si2

Zhongzheng Wu·Yuan Fang·Hang Su·Wu Xie·Peng Li·Yi Wu·Yaobo Huang·Dawei Shen·Balasubramanian Thiagarajan·Johan Adell·Chao Cao·Huiqiu Yuan·Frank Steglich·Yang Liu
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Abstract

The superconducting order parameter of the first heavy-fermion superconductor CeCu2Si2 is currently under debate. A key ingredient to understand its superconductivity and physical properties is the quasiparticle dispersion and Fermi surface, which remains elusive experimentally. Here we present measurements from angle-resolved photoemission spectroscopy. Our results emphasize the key role played by the Ce 4f electrons for the low-temperature Fermi surface, highlighting a band-dependent conduction-f electron hybridization. In particular, we find a very heavy quasi-two-dimensional electron band near the bulk X point and moderately heavy three-dimensional hole pockets near the Z point. Comparison with theoretical calculations reveals the strong local correlation in this compound, calling for further theoretical studies. Our results provide the electronic basis to understand the heavy fermion behavior and superconductivity; implications for the enigmatic superconductivity of this compound are also discussed.

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Zhongzheng Wu, Yuan Fang, Hang Su, Wu Xie, Peng Li, Yi Wu, Yaobo Huang, Dawei Shen, Balasubramanian Thiagarajan, Johan Adell, Chao Cao, Huiqiu Yuan, Frank Steglich, Yang Liu. 2021-05-26. Revealing the Heavy Quasiparticles in the Heavy-Fermion Superconductor CeCu2Si2. https://doi.org/10.1103/physrevlett.127.067002

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