Predicting the thermal conductivity of Si and Ge nanowires

theoretically predict the thermal conductivity versus temperature dependence of Si and Ge nanowires. Three methods are compared: the traditional Callaway and Holland approaches, and our "real dispersions" approach. Calculations with the former two show large disagreements with experimental data. On the contrary, the real dispersions approach yields good agreement with experiments for Si nanowires; between 37 and 115 nm wide, approximately. In all cases, only bulk data are used as inputs for the calculation. Predictions for Ge nanowires of varying diameters are given, enabling future experimental verification.