Softening of a flat phonon mode in the kagome ScV<sub>6</sub>Sn<sub>6</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37863907.
- Also identified by DOI 10.1038/s41467-023-42186-6 and PMC identifier 10589229.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Geometrically frustrated kagome lattices are raising as novel platforms to engineer correlated topological electron flat bands that are prominent to electronic instabilities. Here, we demonstrate a phonon softening at the k<sub>z</sub> = π plane in ScV<sub>6</sub>Sn<sub>6</sub>. The low energy longitudinal phonon collapses at ~98 K and q = [Formula: see text] due to the electron-phonon interaction, without the emergence of long-range charge order which sets in at a different propagation vector q<sub>CDW</sub> = [Formula: see text]. Theoretical calculations corroborate the experimental finding to indicate that the leading instability is located at [Formula: see text] of a rather flat mode. We relate the phonon renormalization to the orbital-resolved susceptibility of the trigonal Sn atoms and explain the approximately flat phonon dispersion. Our data report the first example of the collapse of a kagome bosonic mode and promote the 166 compounds of kagomes as primary candidates to explore correlated flat phonon-topological flat electron physics.