Improvements to the Frequency Domain Perfectly Matched Layer (FDPML) method for fast and large scale phonon transport simulation in nanostructures

Recently, our group has presented a new method for predicting the interaction of phonons with general atomistic domains, called the frequency domain perfectly matched layer (FDPML) method, providing similar information to the phonon AGF method but on a wavevector-resolved basis and with a simpler, faster algorithm. We describe two improvements that now allow for larger computational domain sizes with reduced solution time (1) we describe an MPI approach that is scalable in both memory and time, allowing the method to be used for extremely large simulation domains, for which we show the example of composites with embedded nanoparticles as a useful application case. (2) we show that although the method is intrinsically wavevector-by-wavevector, it is possible to cheaply perform all isofrequency wavevector simulations simultaneously without increasing the computational requirements, significantly speeding transport property calculations requiring integrals over all wavevectors.