Fermion-boson many-body interplay in a frustrated kagome paramagnet.
Journal
Nature communications
ISSN: 2041-1723
Titre abrégé: Nat Commun
Pays: England
ID NLM: 101528555
Informations de publication
Date de publication:
10 Aug 2020
10 Aug 2020
Historique:
received:
23
03
2020
accepted:
01
07
2020
entrez:
12
8
2020
pubmed:
12
8
2020
medline:
12
8
2020
Statut:
epublish
Résumé
Kagome-nets, appearing in electronic, photonic and cold-atom systems, host frustrated fermionic and bosonic excitations. However, it is rare to find a system to study their fermion-boson many-body interplay. Here we use state-of-the-art scanning tunneling microscopy/spectroscopy to discover unusual electronic coupling to flat-band phonons in a layered kagome paramagnet, CoSn. We image the kagome structure with unprecedented atomic resolution and observe the striking bosonic mode interacting with dispersive kagome electrons near the Fermi surface. At this mode energy, the fermionic quasi-particle dispersion exhibits a pronounced renormalization, signaling a giant coupling to bosons. Through the self-energy analysis, first-principles calculation, and a lattice vibration model, we present evidence that this mode arises from the geometrically frustrated phonon flat-band, which is the lattice bosonic analog of the kagome electron flat-band. Our findings provide the first example of kagome bosonic mode (flat-band phonon) in electronic excitations and its strong interaction with fermionic degrees of freedom in kagome-net materials.
Identifiants
pubmed: 32778651
doi: 10.1038/s41467-020-17464-2
pii: 10.1038/s41467-020-17464-2
pmc: PMC7417595
doi:
Types de publication
Journal Article
Langues
eng
Sous-ensembles de citation
IM
Pagination
4003Subventions
Organisme : Gordon and Betty Moore Foundation (Gordon E. and Betty I. Moore Foundation)
ID : GBMF4547/ Hasan
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