Thermal conductance of structured silicon nanocrystals

We calculate the thermal conductance of a structured silicon nanocrystal with a hole of different sizes. The numerical study is based on non-equilibrium molecular dynamics simulations using two potential models for the interatomic interactions: (i) an empirical Tersoff-Brenner (Tersoff) potential; (ii) a semi-empirical tight binding (TB) potential. TB potential model predicts a similar thermal conductance for the nanocrystal with no hole and with a small size hole, which contrasts with the monotonic decrease predicted by Tersoff potential model. In addition, thermal conductance decreasing is higher for TB potential model when the surface-to-volume ratio increases. This points out that to study thermal properties of nanostructures with high surface-to-volume ratio is mandatory the use of potential models with high transferability to take adequately into account the relevant quantum physical effects due to boundaries and surfaces.