近日，韩国浦项科技大学的B. J. Kim&Ki-Seok Kim及其研究团队取得一项新进展。经过不懈努力，他们揭示了过渡金属二硫化物中手性电荷密度波的起源。相关研究成果已于2024年10月14日在国际知名学术期刊《自然—物理学》上发表。
该研究团队阐明了过渡金属二硫属化合物1T-TiSe2中手性电荷密度波形成的机制。基于对称性分析，研究人员证明尽管电荷密度调制和离子位移具有相似的波矢和强耦合，但它们遵循空间群中不同的不可约表示。
这种电荷-晶格对称性的阻挫引发了晶格畸变，进一步破坏了两个分区不共有的所有对称性。这最终导致了手性的产生。这一理论通过拉曼光谱和非弹性X射线散射得到了验证。
据悉，手性指的是缺乏镜像对称性的结构。从亚原子粒子、分子到生物体，手性广泛存在于各种平台中。然而，凝聚态系统中产生手性的潜在机制一直是人们极为关注的研究课题。
附：英文原文
Title: Origin of the chiral charge density wave in transition-metal dichalcogenide
Author: Kim, Kwangrae, Kim, Hyun-Woo J., Ha, Seunghyeok, Kim, Hoon, Kim, Jin-Kwang, Kim, Jaehwon, Kwon, Junyoung, Seol, Jihoon, Jung, Saegyeol, Kim, Changyoung, Ishikawa, Daisuke, Manjo, Taishun, Fukui, Hiroshi, Baron, Alfred Q. R., Alatas, Ahmet, Said, Ayman, Merz, Michael, Le Tacon, Matthieu, Bok, Jin Mo, Kim, Ki-Seok, Kim, B. J.
Issue&Volume: 2024-10-14
Abstract: Chirality refers to a structure that lacks mirror symmetry. It can be observed in a wide range of platforms, from subatomic particles and molecules to living organisms. However, the underlying mechanisms that give rise to chirality in condensed matter systems have been a subject of considerable interest. Here we elucidate the mechanism of chiral charge density wave formation in the transition-metal dichalcogenide 1T-TiSe2. Based on symmetry analysis, we demonstrate that charge density modulations and ionic displacements follow distinct irreducible representations of the space group, despite exhibiting similar wave vectors and a strong coupling. This charge-lattice symmetry frustration induces lattice distortions that further break all symmetries that are not common to both sectors. This ultimately gives rise to chirality. Our theory is verified using Raman spectroscopy and inelastic X-ray scattering.
DOI: 10.1038/s41567-024-02668-w
Source: https://www.nature.com/articles/s41567-024-02668-w