A theoretical insight into phonon heat transport in graphene/biphenylene superlattice nanoribbons: A molecular dynamic study

Manipulating the thermal conductivity of nanomaterials is an efficacious approach to fabricate tailor-made nanodevices for thermoelectric applications. To this end, superlattice nanostructures can be used to achieve minimal thermal conductivity for the employed nanomaterials. Two-dimensional biphenylene is a recently-synthesized sp2-hybridized allotrope of carbon atoms that can be employed in superlattice nanostructures and therefore further investigation in this context is due. In this study, we first determined the thermal conductivity of biphenylene at 142.8 W mK-1 which is significantly lower than that of graphene. As a second step, we studied the effect of the superlattice period ( lp ) on thermal conductivities of the employed graphene/biphenylene superlattice nanoribbons, using molecular dynamics simulations. We calculated a minimum thermal conductivity of 105.5 W mK-1 at lp = 5.066 nm which indicates an achieved thermal conductivity reduction of approximately 97% and 26% when compared to pristine graphene and biphenylene, respectively. This superlattice period denotes the phonon coherent length at which the wave-like behavior of phonons starts prevailing over the particle-like behavior. Finally, the effects of temperature and temperature gradient on the thermal conductivity of superlattice were also investigated.