Highly efficient thermal rectification in carbon/boron nitride heteronanotubes

Abstract

Carbon/boron nitride heteronanotubes (CBNNTs) have attracted considerable attention owing to their unique properties and functions for practical applications in many fields. However, interfacial thermal transport in such heterostructures, which plays a pivotal role in determining their functional properties, is still unknown. In this work, we use non-equilibrium molecular dynamics (NEMD) simulations to study the thermal transport across CBNNTs interface. It is found that the heat flows preferentially from the BNNTs to the CNTs region, demonstrating pronounced thermal rectification (TR) effect. In addition, the TR ratio of zigzag CBNNTs is much more than that of armchair ones, especially under lager temperature bias. With the help of wave packet dynamics simulation and power spectrum calculation, the underlying mechanism of TR in CBNNTs is identified. Furthermore, the influence of system size, ambient temperature and defect density is studied to obtain the optimum conditions for TR. More importantly, we also found that the TR ratio of CBNNTs apparently decreases when taking account of the substrate interaction or tensile strain in practical design for thermal rectifier. Our results provide a certain guidance for designing high-efficiency thermal rectifier based CBNNTs.