A molecular dynamics investigation on thermal conductivity of graphynes

Graphyne is an allotrope of graphene with both sp and sp2 hybridized carbon atoms. In this paper, molecular dynamics simulations are carried out on four different graphynes (α, β, γ, and 6,6,12-graphenes) to explore their thermal conductivity (TC). The difference between the four graphyne structures lies in the different percentages of the acetylenic linkages (triple-bonded carbon linkages). The presence of the acetylenic linkages in graphynes is found to cause a significant reduction in the TC as a result of the associated low atom density in the structures and weak single bonds in the acetylenic linkages. Among the four graphynes considered, the 6,6,12-graphyne shows the most obvious directional anisotropy in the TC. Beside the structure, external strain and temperature are also found to affect the TC of graphynes.