Optical spectroscopy study of the interplay between Dirac electrons, magnetism, and charge density waves in square-net materials

方网材料中狄拉克电子、磁性和电荷密度波之间相互作用的光谱研究

• 批准号: 411090417
• 负责人: Professorin Dr. Christine Kuntscher
• 金额: --
• 依托单位: Lehrstuhl für Experimentalphysik II
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/411090417?language=en
• 关键词: Optical; spectroscopy; study; interplay; between

Square-net materials with topological electronic band structure such as the prototypical nodal-line semimetal ZrSiS are currently intensively investigated. Topological Dirac semimetals possess linearly dispersing electronic bands, which cross at certain points in reciprocal space, and show exceptional physical properties. In nodal-line semimetals the crossing points lie on a line or closed loop, and they can be viewed as 3D analogues of graphene hosting 2D Dirac electrons. Within this project, the ZrSiS-related square-net materials LnSbTe will be studied, where the Ln sites are occupied by lanthanide atoms inducing intrinsic magnetism. Therefore, LnSbTe compounds host a magnetic topological nodal-line semimetallic state at low temperatures. It was furthermore demonstrated that suitable substitution and vacancy concentration cause structural distortion and the development of charge density waves (CDWs) in LnSbxTe2−x-delta compounds, which enables an electronic band engineering and can generate novel topological phases. We will characterize the interplay between Dirac electrons, magnetism, and CDWs in the compounds LnSbxTe2−x-delta in terms of the charge dynamics by temperature-dependent optical spectroscopy. Furthermore, we will explore how external pressure tunes this interplay by optical spectroscopy measurements under hydrostatic pressure, since pressure is expected to strongly affect the CDW-related lattice distortion and hence also the electronic band structure.

具有拓扑电子能带结构的方网材料，如典型的半金属ZrSiS，是目前研究的热点。拓扑狄拉克半金属具有线性分散的电子带，在倒易空间中的某些点交叉，并显示出特殊的物理性质。在半金属中，交叉点位于一条线或闭环上，它们可以被视为承载2D狄拉克电子的石墨烯的3D类似物。在本项目中，将研究与ZrSiS相关的方网材料LnSbTe，其中Ln位置被镧系原子占据，从而产生内禀磁性。因此，LnSbTe化合物在低温下具有磁性拓扑线半金属态。此外，还证明了适当的取代和空位浓度会导致LnSbxTe 2 −x-delta化合物的结构畸变和电荷密度波（CDW）的发展，这使得电子能带工程成为可能，并可以产生新的拓扑相。我们将通过温度依赖的光谱学来表征化合物LnSbxTe 2 −x-delta中狄拉克电子，磁性和CDW之间的相互作用。此外，我们将探讨外部压力如何调谐这种相互作用的光学光谱测量下的静水压力，因为压力预计会强烈影响CDW相关的晶格畸变，因此也电子能带结构。