One-dimensional phonon effects in direct molecular dynamics method for thermal conductivity determination

Abstract

We demonstrate that the use of the direct, heat sourcesink method for thermal conductivity determination via molecular dynamics simulation leads to diverging thermal conductivity with increasing simulation cell length when the cross section of the cell is kept constant. A phonon transport theory based analysis shows that this divergence arises due to discrete phonon phase space sampling leading to behavior characteristics of one-dimensional systems, which are known for size divergent thermal conductivity. We also show that the divergence is particularly strong for thermal conductivity along the elastically soft direction in anisotropic crystals. © 2011 American Institute of Physics.