Chirality-Selective Transport of Benzene Molecules on Carbon Nanotubes

Using molecular dynamics simulations, we predict an effect of chirality on the conduction of benzene molecules along the surface of carbon nanotubes (CNTs) subjected to a thermal gradient. The group drift velocity of the molecules is found to be maximal in the case of an armchair CNT, and to decrease with decreasing chiral angle. This chirality effect on thermodiffusion is induced by a variation in the optimized paths of molecules that change with different electronic overlap at the interface. The mechanism for the thermophoretic transport is identified to be coupled with a gradient of adsorbate-substrate interaction energy, which originates from the anharmonic nature of the van der Waals potential.