1 research outputs found
Antiresonances in the Mid-Infrared Vibrational Spectrum of Functionalized Graphene
We
report anomalous antiresonances in the infrared spectra of doped
and disordered single layer graphene. Measurements in both reflection
microscopy and transmission configurations of samples grafted with
halogenophenyl moieties are presented. Asymmetric transparency windows
at energies corresponding to phonon modes near the Γ and K points
are observed, in contrast to the featureless spectrum of pristine
graphene. These asymmetric antiresonances are demonstrated to vary
as a function of the chemical potential and defect density. We propose
a model that involves coherent intraband scattering with defects and
phonons, thus relaxing the optical selection rule forbidding access
to <b>q</b> ≠ Γ phonons. This interpretation of
the new phenomenon is supported by our numerical simulations that
reproduce the experimental features