Suppression of coherent thermal transport in quasiperiodic graphene-hBN superlattice ribbons

Nanostructured superlattices are promising materials for novel electronic devices due to their adjustable physical properties. Periodic superlattices facilitate coherent phonon thermal transport due to constructive wave interference at the boundaries between the materials. However, it is possible to induce a crossover from coherent to incoherent transport regimes by adjusting the superlattice period. We have recently observed such crossover in periodic graphene-boron nitride nanoribbons as the length of individual domains was increased. In general, transport properties are dominated by translational symmetry and the presence of unconventional symmetries leads to unusual transport characteristics. Here we perform non-equilibrium molecular dynamics simulations to investigate phonon heat transport in graphene-hBN superlattices following the Fibonacci quasiperiodic sequence, which lie between periodic and disordered structures. Our simulations show that the quasiperiodicity can suppress coherent phonon thermal transport in these superlattices. This behavior is related to the increasing number of interfaces per unit cell as the Fibonacci generation increases, hindering phonon coherence along the superlattice. The suppression of coherent thermal transport in graphene-hBN superlattices enables a higher degree of control on heat conduction at the nanoscale, and shows potential for application in the design of novel thermal management devices. (C) 2020 Elsevier Ltd. All rights reserved.