A tunable charge density wave in the kagome metal ScV₆Sn₆

The frustrated interactions between atoms arranged on a kagome lattice produce a wonderful playground for unusual electronic and magnetic physics. Although magnetic frustration initially brought attention to kagome materials, the impact of the features of the electronic structure itself has garnered recent attention. For example, the charge density wave (CDW) in hexagonal-FeGe and AV₃Sb₅ compounds are closely tied to van Hove singularities in their electronic structure.

I will present evidence of a similar CDW in the HfFe₆Ge₆-type kagome metal ScV₆Sn₆ below 92 K. Temperature-dependent physical properties and structural characterization reveal a first-order phase transition into a structurally modulated phase with a wave vector (1/3 1/3 1/3).[1] ScV₆Sn₆ provides an excellent platform to study CDW order in kagome metals because of the many opportunities for chemical tunability and absence of competing orders. Mysteriously, its sister compounds LuV₆Sn₆ and YV₆Sn₆ have no CDW order despite nearly identical electronic structures. I will show how Lu and Y substitution suppresses the CDW in ScV₆Sn₆ revealing clues about the origins of CDW order in kagome metals.