New publication in Scientific Reports – Thermal conductivity of graphene-hBN superlattice ribbons

Our third paper of 2018 “Thermal conductivity of graphene-hBN superlattice ribbons”  has just been published in Scientific Reports, a publication of the Nature Publishing Group.

In this work we investigate coherent (wave-like) and incoherent (particle-like) phonon thermal transport in superlattices graphene and hexagonal boron nitride, which have been produced recently with sharp edges and controlled domain sizes. We employ non-equilibrium molecular dynamics simulations to investigate the thermal conductivity of superlattice nanoribbons with equal-sized domains of graphene and BN. We analyze the dependence of the conductivity with the domain sizes and with the total length of the ribbons, and determine a minimum thermal conductivity of 89 W m−1K−1 for ribbons with a superlattice period of 3.43 nm. The effective phonon mean free path is also determined and shows a minimum value of 32 nm for the same superlattice period. Our results reveal a crossover from coherent to incoherent phonon transport at room temperature as the superlattice period becomes comparable to the phonon coherence length. Analyzing phonon populations relative to the smallest superlattice period, we attribute the minimum thermal conductivity to a reduction in the population of flexural phonons when the superlattice period equals 3.43 nm. The ability to manipulate thermal conductivity using superlattice-based two-dimensional materials, such as graphene-hBN nanoribbons, opens up opportunities for application in future nanostructured thermoelectric devices.

We are particularly proud of this work for two reasons. First, because it is a product of Isaac’s Master’s thesis, my first graduate student supervision ever. Second, because it has been completely developed and executed at UFRN, including the computational support provided by our supercomputing center NPAD. We expect to publish further developments of this work in 2018.

The open access publication is available here.

Coverage by UFRN news.

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