  Niobium halides, Nb3X8 (X = Cl,Br,I), which are predicted two-dimensional
magnets, have recently gotten attention due to their breathing kagome geometry.
Here, we have studied the electronic structure of Nb3Br8 by using
angle-resolved photoemission spectroscopy (ARPES) and first-principles
calculations. ARPES results depict the presence of multiple flat and weakly
dispersing bands. These bands are well explained by the theoretical
calculations, which show they have Nb d character indicating their origination
from the Nb atoms forming the breathing kagome plane. This van der Waals
material can be easily thinned down via mechanical exfoliation to the ultrathin
limit and such ultrathin samples are stable as depicted from the time-dependent
Raman spectroscopy measurements at room temperature. These results demonstrate
that Nb3Br8 is an excellent material not only for studying breathing kagome
induced flat band physics and its connection with magnetism, but also for
heterostructure fabrication for application purposes.
