Strong superconducting pairing strength and pseudogap features in a putative multiphase heavy-fermion superconductor CeRh2As2 by soft point-contact spectroscopy

Qingxin Dong; Tong Shi; Pengtao Yang; Xinyang Liu; Xiaofan Shi; Lei Wang; Junsen Xiang; Hanming Ma; Zhaoming Tian; Jianping Sun; Yoshiya Uwatoko; Genfu Chen; Xinbo Wang; Jie Shen; Rui Wu; Xin Lu; Peijie Sun; Grzegorz Chajewski; Dariusz Kaczorowski; Bosen Wang; Jinguang Cheng

arXiv · 2501.02231

Strong superconducting pairing strength and pseudogap features in a putative multiphase heavy-fermion superconductor CeRh2As2 by soft point-contact spectroscopy

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Abstract

CeRh2As2 is a newly discovered candidate of multiphase heavy-fermion superconductor (Tc=0.3 K) with intriguing physical properties. Here, we employ soft point-contact spectroscopy to investigate its energy gap behaviors in both the normal and superconducting states. The differential conductance below Tc reveals an estimated superconducting energy gap of 2{\Delta}SC=0.24 meV and thus an extremely strong superconducting pairing strength 2{\Delta}SC/kBTc=8.8, which is comparable to those of cuprates and iron-based high-Tc superconductors as well as infinite-layer nickelates. Above Tc, a well-defined pseudogap feature is manifested as a V-shaped dip in the differential conductance spanning an energy scale of 2{\Delta}g=0.95-3.0 meV. The pseudogap feature persists to the highest characteristic temperature of Tg=8-9 K and is gradually suppressed by magnetic field of Bg=9.0T regardless of its direction relative to the crystallographic axes. The observation of pseudogap features prior to the superconducting phase transition enriches the phase diagram of CeRh2As2 and provides a novel platform to study the interplay of unconventional superconductivity and pseudogap phenomena.

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Qingxin Dong, Tong Shi, Pengtao Yang, Xinyang Liu, Xiaofan Shi, Lei Wang, Junsen Xiang, Hanming Ma, Zhaoming Tian, Jianping Sun, Yoshiya Uwatoko, Genfu Chen, Xinbo Wang, Jie Shen, Rui Wu, Xin Lu, Peijie Sun, Grzegorz Chajewski, Dariusz Kaczorowski, Bosen Wang, Jinguang Cheng. 2025-01-04. Strong superconducting pairing strength and pseudogap features in a putative multiphase heavy-fermion superconductor CeRh2As2 by soft point-contact spectroscopy. https://arxiv.org/abs/2501.02231

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