Nicholas Lundgren Research Talk (2020 Larock Conference, Physical/Analytical Presentation #4)
From Lee-Ping Wang
Title: The Effects of Germanium Concentration on the Thermal Conductivity of Amorphous Silicon-Germanium
Authors: Nicholas Lundgren, Giuseppe Barbalinardo, and Davide Donadio
Abstract: Many amorphous solids are used as component materials in applications where the control of the temperature is important for component lifetimes and efficient use of power. Amorphous silicon-germanium films, specifically, are often used in solar power capture where it is desirable to have constant performance under variable heat flux. Unfortunately, the theoretical understanding of thermal transport in these systems is hazy because of the lack of short-range structure on which most computational models rely. By monitoring the thermal conductivity of a two-species amorphous system change in response to relative concentrations, we provide a description of the role of the system disorder in the thermal conductivity measurement. The thermal conductivities are calculated for amorphous silicon germanium systems with germanium concentration ranging from 0 to 100% using the quasi-harmonic Green Kubo approach to lattice dynamics developed by IIsaeva et. al. in 2019. This work provides an atomistic understanding of how the disorder affects heat transport properties in semiconductors with important technological applications, and represents a step forward in the path of artificially designed material with selected thermal properties.