  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.
