Pressure Induced 18 K Superconductivity and Two Superconducting Phases in CuIr2S4
Bijuan Chen, Yuhao Gu, Dong Wang, Dexi Shao, Wen Deng, Xin Han, Meiling Jin, Jing Song, Yu Zeng, Hirofumi Ishii, Yen-Fa Liao, Dongzhou Zhang, Jianbo Zhang, Youwen Long, Jinlong Zhu, Liuxiang Yang, Hong Xiao, Jia-cai Nei, Youguo Shi, Changqing Jin, Jiangping Hu, Ho-kwang Mao, Yang Ding
公開日: 2024/11/7
Abstract
We report pressure-induced superconductivity in the spinel CuIr2S4 with a transition temperature Tc reaching 18.2 K, establishing a new record for this class of materials and surpassing the decades-old limit of 13.7 K. Our electrical transport and synchrotron X-ray diffraction studies up to 224 GPa reveal the emergence of \textbf{two distinct superconducting phases} from a charge-ordered insulating state. The first phase (SC-I) appears around 18 GPa, forming a superconducting dome that peaks at 18.2 K at 133 GPa. Above 111.8 GPa, a second, lower-Tc phase (SC-II) emerges and coexists with SC-I over a broad pressure range. These superconducting phases are intimately linked to a cascade of structural transitions that systematically distort the frustrated pyrochlore lattice of Ir atoms. Our results redefine the potential for superconductivity in spinels and showcase a pathway to high-Tc pairing directly from a correlated insulating state driven by lattice tuning.