• Using    angle-resolved    photoemission    spectroscopy    supported    by theoretical   calculations,   we   studied   the   electronic   structure   of   a breathing kagome semiconductors Nb3I8and Nb3Br8.
  • Results:(i) Observation of flat and weakly dispersing bands (see figure alongside)  in the electronic structure, (ii) these bands show sensitivity to light    polarization,    (iii)    Calculations    qualitatively    reproduce    the observations and show these bands come from Nb-d bands implying the breathing kagome origination of the bands. Nb3I8: https://doi.org/10.1038/s43246-022-00318-3
  • Significance:(i)   Insight   into   the   flat   band   physics   coming   from breathing  kagome  lattice  in  an  exfoliable  van  der  Waals  system, (ii)  flat bands   give   rise   to   electronic   correlations   in   a   system   where   the constituent elements are not supposed to provide correlated electrons.
  • Outlook:Substitution  of  halogen  atom  in  Nb3Br8-xIx  (x=0-8)  would  allow us to study the tunability of the flat and weakly dispersing bands in this family of materials..