Computational Modelling of Silicon Phononic Crystals

Prof. Ralf Meyer
SHARCNET Research Chair,
Department of Mathematics and Computer Science,
Laurentian University

Abstract

Phononic crystals are periodically structured, synthetic materials that allow control of the propagation of elastic waves. Through the choice of the parameters of the periodic structuring opens the phonon dispersion relations can be modified and vibrational band gaps can be created. Phononic crystals have numerous potential applications in areas such as noise control, ultrasound imaging and telecommunications. Since the principal carriers of heat in non-metallic materials are phonons, nanoscale phononic crystals with operating frequencies in the THz regime can be utilized to control the flow of heat. This has potential applications in energy harvesting and novel heating or cooling technologies.

In this work, molecular dynamics simulations and finite element computational are used to study the vibrational band structure and thermal resistance of silicon phononic crystals. The results show how a binary honeycomb lattice can be used to selectively control the size of the lowest vibrational band gap. The thermal resistance of the model systems is determined with the help of Reverse Non-Equilibrium Molecular Dynamics (RNEMD). The results show differences in the scaling behaviour of the thermal resistance for phononic crystals and nanowires.