Our first publication of 2022 “Thermal conductivity of Thue–Morse and double-period quasiperiodic graphene-hBN superlattices” has just been published in the International Journal of Heat and Mass Transfer.
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. In 2018 we 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. In 2020 we showed that the quasiperiodicity can suppress coherent phonon thermal transport in superlattices following the Fibonacci quasiperiodic sequence, which lie between periodic and disordered structures. Finally, in our latest publication we perform non-equilibrium molecular dynamics simulations to investigate phonon heat transport in graphene-hBN superlattices following the Thue-Morse and double-period quasiperiodic sequences, and show that coherent transport is indeed suppressed due to phonon localization caused by increase in superlattice period. We also obtain a general expression for conductivity as a function of quasiperiodic generation and supercell size, which might be useful for superlattice following other sequences.
This is the latest publication, but hopefully not the last, from Isaac’s PhD dissertation. It was completely carried out within our research group at UFRN and UFPE, and we are grateful for the computational support provided by the supercomputing center at UFRN (NPAD).