Flat bands and giant light-matter interaction in hexagonal boron nitride - Laboratoire Charles Coulomb (L2C) Accéder directement au contenu
Article Dans Une Revue Physical Review Letters Année : 2021

Flat bands and giant light-matter interaction in hexagonal boron nitride

Christine Elias
  • Fonction : Auteur
  • PersonId : 1047974
Pierre Valvin
  • Fonction : Auteur
  • PersonId : 987631
Christian Lhenoret
  • Fonction : Auteur
  • PersonId : 1111132
J. Li
  • Fonction : Auteur
A. Ouerghi
Bernard Gil
  • Fonction : Auteur
  • PersonId : 995090

Résumé

Dispersionless energy bands in k space are a peculiar property gathering increasing attention for the emergence of novel electronic, magnetic, and photonic properties. Here, we explore the impact of electronic flat bands on the light-matter interaction. The van der Waals interaction between the atomic layers of hexagonal boron nitride induces flat bands along specific lines of the Brillouin zone. The macroscopic degeneracy along these lines leads to van Hove singularities with divergent joint density of states, resulting in outstanding optical properties of the excitonic states. For the direct exciton, we report a giant oscillator strength with a longitudinal-transverse splitting of 420 meV, a record value, confirmed by our ab initio calculations. For the fundamental indirect exciton, flat bands result in phonon-assisted processes of exceptional efficiency, that compete with direct absorption in reflectivity, and that make the internal quantum efficiency close to values typical of direct band gap semiconductors.
Fichier principal
Vignette du fichier
PRL-FlatBands2021.pdf (630.18 Ko) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte

Dates et versions

hal-03353115 , version 1 (24-09-2021)

Identifiants

Citer

Christine Elias, Giorgia Fugallo, Pierre Valvin, Christian Lhenoret, J. Li, et al.. Flat bands and giant light-matter interaction in hexagonal boron nitride. Physical Review Letters, 2021, 127 (13), pp.137401. ⟨10.1103/PhysRevLett.127.137401⟩. ⟨hal-03353115⟩
129 Consultations
544 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More