Journal: Computer Physics Communications

Article Title: A coherent phonon pulse model for transient phonon thermal transport

doi: 10.1016/j.cpc.2015.05.008

Figure Lengend Snippet: Fig. 1: (a) Wave packet composed of Gaussian waves. (b) Fourier Transform of the wave packet in (a), inset in (b) is the PDOS of SiNW at 500K computed from MD results. In Fig. 2, we present the schematic of the computational model (~600,000 atoms, ~ 3 3 1.2 nm nm m μ × × ). The general- purpose molecular dynamics software package LAMMPS [45] is employed in all the simulations in this work without assuming periodic boundary conditions. Velocity Verlet algorithm with time step of 0.55fs is used, which is about 1% of the shortest phonon period in Si lattice. Before the heat pulse is generated, the MD model is equilibrated at 0.1K to allow only the scattering events that involve phonons generated from the heat source. Note that with a higher initial temperature, the scattering events involve the original thermal phonons can be naturally incorporated. Thereafter, the heat pulse constructed by CPP model is applied in the middle of the Grain I, and naturally allowed in the MD simulations to propagate across the GBs into the Grain II (positive z) and the Grain III (negative z) at the two ends of the NW. With the heat source region located at the center of the Grain I, unwanted phonon scatterings by free boundaries are avoided. Since the model is symmetric, only half of which is of interest, we take it as a

Article Snippet: The generalpurpose molecular dynamics software package LAMMPS [45] is employed in all the simulations in this work without assuming periodic boundary conditions.

Techniques: Software, Generated, Construct