Pressure-induced crystal structural and insulator-metal transitions in the quantum spin liquid candidate CsYbSe2

作者：Raimundas Sereika, Xilong Xu, Yizhou Wang, Li Yang, Dongzhou Zhang, Stella Chariton, Jie Xing, Athena S. Sefat, Yogesh K. Vohra, Wenli Bi · 发表于：Physical review. B./Physical review. B · 年份：2023 · DOI：10.1103/physrevb.108.174106 · 被引用次数：5 · 研究领域：Advanced Condensed Matter Physics、Magnetic and transport properties of perovskites and related materials、Physics of Superconductivity and Magnetism

${\mathrm{CsYbSe}}_{2}$ has an ideal triangular-lattice geometry with pronounced two-dimensionality, pseudospin-1/2 nature, and the absence of structural disorder. These excellent characteristics favor a quantum spin-liquid realization in this material. In this work, we applied quasihydrostatic compression methods to explore the structural behaviors. Our study reveals that ${\mathrm{CsYbSe}}_{2}$ undergoes a structural transition around 24 GPa, accompanied by a large volume collapse of $\mathrm{\ensuremath{\Delta}}\mathrm{V}$ /$V{}_{0}\phantom{\rule{4pt}{0ex}}\ensuremath{\sim}13%$. The ambient hexagonal structure with the space group $P{6}_{3}/mmc$is lowered to the tetragonal structure ($P4$/mmm) under high pressure. Meanwhile, the color of ${\mathrm{CsYbSe}}_{2}$ changes gradually from red to black before the transition. Dramatic pressure-induced changes are clarified by the electronic structure calculations from the first principles, which indicate that the initial insulating ground state turns metallic in a squeezed lattice. These findings highlight Yb-based dichalcogenide delafossites as an intriguing material to probe novel quantum effects under high pressure.