Stability frontiers in the AM${}_6$X${}_6$ kagome metals: The LnNb${}_6$Sn${}_6$ (Ln:Ce-Lu,Y) family and density-wave transition in LuNb${}_6$Sn${}_6$

Abstract

The kagome motif is a versatile platform for condensed matter physics, hosting rich interactions between magnetic, electronic, and structural degrees of freedom. In recent years, the discovery of a charge density wave (CDW) in the AV${}_3$Sb${}_5$ superconductors and structurally-derived bond density waves in FeGe and ScV${}_6$Sn${}_6$ have stoked the search for new kagome platforms broadly exhibiting density wave (DW) transitions. In this work, we evaluate the known AM${}_6$X${}_6$ chemistries and construct a stability diagram that summarizes the structural relationships between the $\approx$125 member family. Subsequently we introduce our discovery of the broader LnNb${}_6$Sn${}_6$ (Ln:Ce-Nd,Sm,Gd-Tm,Lu,Y) family of kagome metals and an analogous DW transition in LuNb${}_6$Sn${}_6$. Our X-ray scattering measurements clearly indicate a (1/3, 1/3, 1/3) ordering wave vector ($\sqrt{3}\times \sqrt{3}\times 3$ superlattice) and diffuse scattering on half-integer $L$-planes. Our analysis of the structural data supports the ``rattling mode'' DW model proposed for ScV${}_6$Sn${}_6$ and paints a detailed picture of the steric interactions between the rare-earth filler element and the host Nb-Sn kagome scaffolding. We also provide a broad survey of the magnetic properties within the HfFe${}_6$Ge${}_6$-type LnNb${}_6$Sn${}_6$ members, revealing a number of complex antiferromagnetic and metamagnetic transitions throughout the family. This work integrates our new LnNb${}_6$Sn${}_6$ series of compounds into the broader AM${}_6$X${}_6$ family, providing new material platforms and forging a new route forward at the frontier of kagome metal research.

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Cited by in corpus (13)

• Kagome metals
• Kagome Metal GdNb${}_6$Sn${}_6$: A 4d Playground for Topological Magnetism and Electron Correlations
• Discovery of an Intermediate Nematic State in a Bilayer Kagome Metal ScV6Sn6
• Magnetic order and physical properties of the Kagome metal UNb${}_6$Sn${}_6$
• Incommensurate and commensurate antiferromagnetic orders in the kagome compound UV${}_6$Sn${}_6$
• Successive orthorhombic distortions in kagome metals by molecular orbital formation
• Pressure suppresses the density wave order in kagome metal LuNb${}_6$Sn${}_6$
• Interacting spin and charge density waves in kagome metal FeGe
• Kekulé order from diffuse nesting near higher-order Van Hove points
• Magnetism of kagome metals $\left({\text{Fe}}_{1-x}{\text{Co}}_x\right)\text{Sn}$ studied by $\mu$SR
• Beyond kagome: $p$-bands in kagome metals
• Single crystal growth, structural and physical properties, and absence of a charge density wave in Ti_{0.85}Fe6Ge6
• Synergistic doping and stabilization of magnetically tunable LnTi${}_3$(Sb,Sn)${}_4$ (Ln:Ce--Gd) kagome metals