Enhancement effect of asymmetry on the thermal conductivity of double-stranded chain systems

Using nonequilibrium molecular dynamics simulations, we study the thermal conductivity of asymmetric double chains. We couple two different single chains through interchain coupling to build three kinds of asymmetric double-stranded chain system: intrachain interaction, external potential, and mass asymmetric double chains. It is reported that asymmetry is helpful in improving the thermal conductivity of the system. We first propose double-heat flux channels to explain the influence of asymmetric structures on the thermal conductivity. The phonon spectral behaviour and finite size effect are also included.