  Condensed matter systems with flat bands have been the center of research
interest in recent years as they provide a platform for the emergence of exotic
many-body states, such as superconductivity, ferromagnetism, and the fractional
quantum Hall effect. However, realization of materials possessing at bands near
the Fermi level experimentally is very rare. Here, we report the experimental
observation of flat bands in a weakly-correlated system YRu2Si2 employing
angle-resolved photoemission spectroscopy (ARPES) which is supported by
first-principles calculations. These flat bands originate from Ru d orbitals
and are found to be sensitive to the polarization of light. In addition, ARPES
data revealed surface and bulk Dirac-like bands. The observed ARPES data is in
excellent agreement with the density functional theory results. The presence of
both flat bands and Dirac-like bands in YRu2Si2 suggest a unique synergy of
correlation and topology in this material belonging to the centrosymmetric
tetragonal ThCr2Si2-type structure thus establishing a new platform to
investigate flat band physics in combination with non-trivial topological
states in a weakly correlated system.
