We have investigated the effect of mass contrast on alloy phonon scattering in mass-substituted Lennard-Jones crystals. By calculating the mass-difference phonon scattering rate using a modal analysis method based on molecular dynamics, we have identified the applicability and limits of the widely-used mass-difference perturbation model in terms of magnitude and sign of the mass difference. The result of a phonon -mode-dependent analysis reveals that the critical phonon frequency, above which the mass-difference perturbation theory fails, decreases with the magnitude of the mass difference independently of its sign. This gives rise to a critical mass contrast, above which the mass-difference perturbation model noticeably underestimates the lattice thermal conductivity.
@article{arxiv.1506.02365,
title = {Influence of mass contrast in alloy phonon scattering},
author = {Takuma Shiga and Takuma Hori and Junichiro Shiomi},
journal= {arXiv preprint arXiv:1506.02365},
year = {2015}
}