Thermal conductivity prediction of nanoscale phononic crystal slabs using a hybrid lattice dynamics-continuum mechanics technique

• Published in: AIP advances 2011-12, Vol.1 (4), p.041403-041403-14
• Main Authors: Reinke, Charles M., Su, Mehmet F., Davis, Bruce L., Kim, Bongsang, Hussein, Mahmoud I., Leseman, Zayd C., Olsson-III, Roy H., El-Kady, Ihab
• Format: Article
• Language: English
• ISSN: 2158-3226; 2158-3226
• DOI: 10.1063/1.3675918

Recent work has demonstrated that nanostructuring of a semiconductor material to form a phononic crystal (PnC) can significantly reduce its thermal conductivity. In this paper, we present a classical method that combines atomic-level information with the application of Bloch theory at the continuum level for the prediction of the thermal conductivity of finite-thickness PnCs with unit cells sized in the micron scale. Lattice dynamics calculations are done at the bulk material level, and the plane-wave expansion method is implemented at the macrosale PnC unit cell level. The combination of the lattice dynamics-based and continuum mechanics-based dispersion information is then used in the Callaway-Holland model to calculate the thermal transport properties of the PnC. We demonstrate that this hybrid approach provides both accurate and efficient predictions of the thermal conductivity.