报告题目 (Title)：A colossal first-order charge density wave transition in 3D R2Ir3Si5 (R = Lu, Er, Ho) and its interplay with magnetism（在三维R2Ir3Si5 (R = Lu, Er, Ho) 体系中存在的庞电荷密度波一级相变以及它和磁性的相互作用）

报告人 (Speaker)：Sitaram Ramakrishnan, Assistant Professor（Hiroshima University）

报告时间 (Time)：2022年12月20日 (周二) 15:00-17:00

报告地点 (Place)：腾讯会议704-121-735（密码1220）

邀请人 (Inviter)：鲍金科

主办部门 (Organizer)：理学院物理系

报告摘要 (Abstract)：

R2Ir3Si5 (R = Lu, Er, Ho) at ambient conditions crystallizes in the orthorhombic Ibam, U2Co3Si5 structure type [1]. Previously, physical property measurements were performed for single-crystal Lu2Ir3Si5 where both charge density wave (CDW) and superconductivity (SC) was found at 200 K and 2 K [2]. However, the symmetry of the crystal in the CDW phase was left unexplored. We have studied both Lu2Ir3Si5 and Er2Ir3Si5 via single crystal x-ray diffraction (SXRD) down to 20 K where we found the structure is actually triclinic I-1 despite the strong monoclinic distortion of the lattice accompanied satellite reflections at q = δ(1 2 1), δ = 0.23 ∼ 0.25 and that the Ir-Ir band is responsible for the CDW [3, 4]. For Er2Ir3Si5 we also found from magnetic susceptibility that the CDW is strongly coupled with the magnetism [4].

Currently, upon investigation of another isostructural compound Ho2Ir3Si5 we find that it follows a similar pattern. All three compounds undergo a first-order CDW transition at 200 K for Lu, 150 K for Er and 110 K for Ho. Although, the CDW does not reside on the R atoms, the TCDW is influenced by it. Here I will present the atomic mechanisms of the CDW and its behavior with magnetism in the R2Ir3Si5 family elucidating the similarities and subtle differences between them.

[1] Y. Singh et al., Phys. Rev. B 71, 045109 (2005).

[2] N. Sangeetha et al., Phys. Rev. B 91, 205131 (2015).

[3] S. Ramakrishnan et al., Phys. Rev. B 104, 054116 (2021).

[4] S. Ramakrishnan et al., Phys. Rev. B 101, 060101(R) (2020).