Simulation of phonon transport across a non-polar nanowire junction using an atomistic Green's function method

W Zhang, Birck Nanotechnology Center, Purdue University
N Mingo, 2NASA-Ames Center for Nanotechnology
Timothy Fisher, Birck Nanotechnology Center, Purdue University

Abstract

Phonon transport across a non-polar nanowire situated between two semi-infinite contacts is simulated in this paper using the atomistic Green's function method. Abrupt geometric changes between the nanowire and bulk contacts are handled by self-energy matrices obtained from bare surface Green's functions. Transport properties such as phonon transmission functions and thermal conductances are calculated, and their dependencies on the interatomic potential, length, diameter, shape, and lattice orientation are investigated. The results reveal that the overall thermal conductance of the nanowire-bulk-contact structure increases with nanowire diameter while the normalized thermal conductance approaches an asymptotic value. Thermal conductance decreases significantly with increasing nanowire length and converges to that of the single-contact case. This method can be generalized to study phonon transport through a variety of nanostructures between bulk contacts.

Discipline(s)

Nanoscience and Nanotechnology