Phonon Transport in Amorphous-Coated Nanowires: an Atomistic Green Function Approach

An approach is presented for the atomistic study of phonon transport in real dielectric nanowires via Green functions. The formalism is applied to investigate the phonon flow through nanowires coated by an amorphous material. Examples for a simple model system, and for real Si nanowires coated by silica are given. New physical results emerge for these systems, regarding the character of the transition from ballistic to diffusive transport, the low temperature thermal conductance, and the influence of the wire-coating interface on the thermal transport. An efficient treatment of phonon scattering by the amorphous coating is also developed, representing a valuable tool for the investigation of thermal conduction through amorphous-coated nanowires.