A Heterogeneous Multiscale Model for Interfacial Thermal Transport

While nonequilibrium molecular dynamics (MD) simulations are capable of producing accurate results for mesoscale models, the simulations for a few million molecules can take considerable duration even when run on multiple processors. However, the alternative continuum simulations, while faster, cannot account for any temperature discontinuities at interfaces, and as such, can be rather inaccurate. We present a solution to this by incorporating both models into a multiscale computational scheme, where MD simulations are run over regions where temperature discontinuities are expected, while SSPH simulations are carried out over the remainder of the domain. In order to validate our model, we investigate thermal transport across a Si-Ge nanoscale interface that is embedded within a mesoscale system using both the novel multiscale model and pure MD simulations. The results indicate that the output from the coupled MD-SSPH model is in good agreement with those of the pure MD simulation when the boundary temperatures are specified. However, as SSPH does not account for phonon scattering at nonperiodic reflective boundaries, the local temperatures obtained from the multiscale model tend to be higher than those for the pure MD simulation when boundary flux is specified.