Transporte térmico em nanofitas de grafeno-nitreto de boro

Abstract

The ability to manipulate thermal properties of superlattices can help in finding the most promising materials for applications in nanotechnology. Through nonequilibrium molecular dynamics simulations, we investigate the thermal transport in graphene-boron nitride nanoribbons (BNC nanoribbons), alternating periodically equivalent amounts of graphene and boron nitride along its length, by naming the size of each domain pair (graphene-boron nitride) a lattice period. This work shows that the thermal conductivity in BNC nanoribbons varies non-monotonically for different lattice periods, which can thus be controlled according to the domains of graphene and boron nitride. This allows the identification of a lattice period that provides the lowest heat conduction in these superlattices. Accordingly, for nanoribbons with lattice period 3; 43 nm, we find a thermal conductivity of 89 W=m K. This value is much lower than the value found for both graphene and boron nitride isolated. The thermal transport in BNC nanoribbons is dominated by vibrations in their crystal lattice (phonons). We associate this non-monotonic behavior of the thermal conductivity of this super-lattice with the thermal transport of coherent and incoherent phonons. Through the density of vibrational states (VDOS) and phonon dispersion we analyze its vibrational spectrum.