Low-frequency modes in the Raman spectrum of s p − s p 2 nanostructured carbon

摘要: Amorphous carbon films with $sp\text{\ensuremath{-}}s{p}^{2}$ hybridization, produced by supersonic cluster beam deposition, shows the presence of both polyynic and cumulenic species [L. Ravagnan et al., Phys. Rev. Lett. 98, 216103 (2007)]. Here, we present an in situ Raman characterization low-frequency vibrational region $(400\char21{}800\text{ }{\text{cm}}^{\ensuremath{-}1})$ at different temperatures. We report two peaks 450 $720\text{ }{\text{cm}}^{\ensuremath{-}1}$. The lower frequency peak evolution variation $sp$ content it can be attributed, support density functional theory simulations, to bending modes linear structures. }{\text{cm}}^{\ensuremath{-}1}$ does not vary attributed a feature states activated disorder $s{p}^{2}$ phase.