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arXiv · 2509.22473

Competing $s$-wave pairing in overdoped $t$-$J$ model

Wayne Zheng·Tao Cheng·Zheng-Yuan Yue·Fu-Chun Zhang·Wei-Qiang Chen·Zheng-Cheng Gu
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Abstract

The $d$-wave pairing symmetry has long been considered a defining feature of high-temperature superconductivity in cuprates. In this work, we reveal that $s$-wave pairing states exhibit variational energies comparable to the $d$-wave state in a square $t$-$J$ model, particularly at high doping levels ($\delta\gtrsim 15\%$) by using the state-of-the-art tensor network simulation. This surprising result suggests that $s$-wave pairing may play an important role in the cuprate phase diagram, especially for the overdoped region. Our findings provide a potential resolution to discrepancies in recent Josephson tunneling experiments on twisted bilayer cuprates and offer new insights into the evolution of pairing symmetry with doping.

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Wayne Zheng, Tao Cheng, Zheng-Yuan Yue, Fu-Chun Zhang, Wei-Qiang Chen, Zheng-Cheng Gu. 2025-09-26. Competing $s$-wave pairing in overdoped $t$-$J$ model. https://arxiv.org/abs/2509.22473

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