The thermal conductivity of SiGe heterostructure nanowires with different cores and shells

Non-equilibrium molecular dynamics (NEMD) simulation is performed to investigate thermal conductivities of two kinds of SiGe heterostructure nanowires (NWs), core(Si)/shell(Ge) and core(Ge)/(Si) NWs, using different interaction potentials between core and shell atoms. The influence of the proportion of core particles on the overall thermal conductivity of NWs is studied as well. Simulation results demonstrate that thermal conductivities of each kind of NWs with strong potential between core and shell atoms are higher than those of their counterparts with weak interaction between Si and Ge atoms. It is also found that thermal conductivities of both kinds of Si/Ge heterostructure NWs reduce with the decrease of the proportion of core atoms when the shell is not very thick.

► Van der Waals and covalent interactions between the core and shell are compared.
► The role of shell in core–shell nanowireʼs thermal conductivity is investigated.
► A good heat conductor should be viewed as shell to get low thermal conductivity.
► The thermal conductivity is influenced by the proportion of core particles.