Size effect of lattice thermal conductivity across nanoscale thin films bymolecular dynamics simulations

Thermal conductivity in the normal direction of ultra-thin dielectric films is predicted by molecular dynamics calculations for argon crystal. For fil m thicknesses of about 2-10nm within which real measurements cannot yet be implemented, the size dependence of lattice thermal conductivity is capture d and a remarkable thermal conductivity drop is found as compared with bulk experimental data. This size effect demonstrates that phonon-boundary scat tering in thin films may also be very significant at high temperatures even above the Debye temperature. The influence of different potential models i s examined according to the comparison between results from the Lennard-Jon es potential and a soft-sphere potential.