Three-dimensional quantum Griffiths singularity in bulk iron-pnictide superconductors
Abstract
The quantum Griffiths singularity (QGS) is a phenomenon driven by quenched disorders that break conventional scaling invariance and result in a divergent dynamical critical exponent during quantum phase transitions (QPT). While this phenomenon has been well-documented in low-dimensional conventional superconductors and in three-dimensional (3D) magnetic metal systems, its presence in 3D superconducting systems and in unconventional high-temperature superconductors (high-Tc SCs) remains unclear. In this study, we report the observation of robust QGS in the superconductor-metal transition (SMT) of both quasi-2D and 3D anisotropic unconventional high-Tc superconductor CaFe1-xNixAsF (x < 5%) bulk single crystals, where the QGS states persist to up to 5.3 K. A comprehensive quantum phase diagram is established that delineates the 3D anisotropic QGS of SMT induced by perpendicular and parallel magnetic field. Our findings reveal the universality of QGS in 3D superconducting systems and unconventional high-Tc SCs, thereby substantially expanding the range of applicability of QGS.
Cite
@article{arxiv.2406.10193,
title = {Three-dimensional quantum Griffiths singularity in bulk iron-pnictide superconductors},
author = {Shao-Bo Liu and Congkuan Tian and Yongqing Cai and Hang Cui and Xinjian Wei and Mantang Chen and Yang Zhao and Yuan Sui and Shuyue Guan and Shuang Jia and Yu Zhang and Ya Feng and Jiankun Li and Jian Cui and Yuanjun Song and Tingting Hao and Chaoyu Chen and Jian-Hao Chen},
journal= {arXiv preprint arXiv:2406.10193},
year = {2026}
}
Comments
17 pages, 4 figures