Nonlinear breatherlike localized modes in C ₆₀ nanocrystals

We study the dynamics of nanoclusters composed of C ₆₀ fullerene molecules. We reveal that such composite nanostructures can support long-lived strongly localized nonlinear modes, which resemble discrete breathers in simple nonlinear lattices. In these localized modes, the vibrational energy density is localized predominantly at one of the C ₆₀ molecules, and it decays rapidly away from the mode. Our numerical simulations demonstrate that, at room temperatures, the lifetime of such nonlinear localized modes may exceed tens of picoseconds. Consequently, we observe that C ₆₀ nanoclusters demonstrate anomalously slow thermal relaxation when the temperature gradient decays in accord with a power law, thus violating the Cattaneo-Vernotte law of thermal conductivity.