Characterization of phonon density of states of a graphene junction beyond nearest neighbor interactions

Abstract

Graphene has exceptional thermal properties that has presented a wide range of applications. Ballistic thermal transport in graphene due to phonons was made possible by placing a zigzag graphene junction in the middle of a heat sink and a heat source- which induced a temperature gradient that caused heat to flow through the junction. Following the harmonic oscillator model for the graphene junction, interlayer and intralayer interactions were derived beyond nearest neighbors. This paper aims to characterize the zigzag graphene junction's phonon density of states and examine the effects of adding next nearest neighbors and varying the bond stretching force constant, k_s, on the next nearest neighbor interactions. We observed a wider distribution of energies when adding next nearest neighbor interactions at equal k_s. Varying k_s showed similar results as this indicates the strength of interaction between the next nearest neighboring atoms.