CuIr2Se4、CuRh2S4和CuRh2Se4在压力下的耦合结构演化与电子演化
Coupled structural and electronic evolution under pressure in CuIr2Se4, CuRh2S4, and CuRh2Se4
- Nagoya University（名古屋大学）
- Okayama University（冈山大学）
- The Institute for Solid State Physics, The University of Tokyo（东京大学固体物理研究所）
- Kitasato University（北里大学）
- The University of Electro-Communications（电气通信大学）
- Japan Synchrotron Radiation Research Institute (JASRI)（日本同步辐射研究机构（JASRI））
- Kyoto University（京都大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究通过高压X射线衍射和电阻测量，发现三种尖晶石硫族化合物在压力下形成单斜相并伴随绝缘化转变，同时首次报道CuIr2Se4常压超导，揭示结构与电子演化的耦合关系。
AI中文摘要：
尖晶石硫族化合物为研究金属态、超导态和压力诱导绝缘态之间的相互作用提供了一个平台。在此，我们结合同步辐射粉末X射线衍射和电阻率测量，研究了CuIr2Se4、CuRh2S4和CuRh2Se4在超出先前探索范围的压力区间内的压力演化行为。高压衍射揭示出这三种化合物均具有密切相关的单斜超胞。对于CuIr2Se4和CuRh2S4，基于密度泛函理论弛豫的结构模型进行约束轮廓拟合，结果与Phase-IV型键歧化结构相容，而CuRh2Se4的数据则确定了一个相容的单斜晶胞，但未能解析其原子尺度的有序模式。绝缘类输运在CuIr2Se4中于较窄的压力区间内突然出现，而在含Rh化合物中则于更宽的压力区间内逐渐发展，这与它们各自的结构转变密切相关。我们还确立了CuIr2Se4在常压下先前未报道的体超导电性：零电阻在0.29 K时实现，伴随的交流抗磁响应与近乎完全的超导屏蔽一致。这些结果确立了高压单斜相的形成与向绝缘输运演化之间的密切关系，并表明过渡金属和硫族元素的替代在紧密相关的结构框架内调节了特征压力尺度以及与超导电性的竞争。
英文摘要：
Spinel chalcogenides provide a platform for investigating the interplay among metallic, superconducting, and pressure-induced insulating states. Here, we combine synchrotron powder X-ray diffraction and electrical-resistivity measurements to investigate the pressure evolution of CuIr2Se4, CuRh2S4, and CuRh2Se4 over pressure ranges extending beyond those previously explored. High-pressure diffraction reveals closely related monoclinic supercells in all three compounds. For CuIr2Se4 and CuRh2S4, constrained profile fits based on structural models relaxed using density functional theory are compatible with Phase-IV-type bond-disproportionated structures, whereas the data for CuRh2Se4 establish a compatible monoclinic unit cell without resolving its atomic-scale ordering pattern. Insulating-like transport develops abruptly over a narrow pressure range in CuIr2Se4 but more gradually over broader pressure ranges in the Rh-based compounds, in close correspondence with their respective structural transformations. We also establish previously unreported bulk superconductivity in CuIr2Se4 at ambient pressure: zero resistance is attained at 0.29 K, and the accompanying ac diamagnetic response is consistent with nearly complete superconducting shielding. These results establish a close relationship between the formation of the high-pressure monoclinic phases and the evolution toward insulating transport, and demonstrate that transition-metal and chalcogen substitutions tune the characteristic pressure scales and the competition with superconductivity within a closely related structural framework.
