Abstract:
Optimization of thermal conductivity of nanomaterials enables the fabrication of tailor-made
nanodevices for thermoelectric applications. Superlattice nanostructures are correspondingly
introduced to minimize the thermal conductivity of nanomaterials. Herein we computationally
estimate the effect of total length and superlattice period ( lp ) on the thermal conductivity of graphene/
graphane superlattice nanoribbons using molecular dynamics simulation. The intrinsic thermal
conductivity ( ) is demonstrated to be dependent on lp . The of the superlattice, nanoribbons
decreased by approximately 96% and 88% compared to that of pristine graphene and graphane,
respectively. By modifying the overall length of the developed structure, we identified the ballisticdiffusive
transition regime at 120 nm. Further study of the superlattice periods yielded a minimal
thermal conductivity value of 144 W m−
1 k−
1 at lp = 3.4 nm. This superlattice characteristic is connected
to the phonon coherent length, specifically, the length of the turning point at which the wave-like
behavior of phonons starts to dominate the particle-like behavior. Our results highlight a roadmap for
thermal conductivity value control via appropriate adjustments of the superlattice period.