Condução de calor em nanofitas quase-periódicas de grafeno-hBN

Abstract

The development of nanotechnology requires an increasing understanding of the phenomena related to nanoscale heat transport, in order to find promising strategies for thermal management in miniaturized electronic devices. In this sense, semiconductor superlattices (whose phonons are the main heat carriers) have been shown to be an ideal platform for the exploration of these phenomena, as they allow to control their physical properties by adjusting only their superlattice period (supercell size). In the present study, non-equilibrium molecular dynamics simulations were performed to investigate thermal transport in graphene-hBN superlattices in the face of a gradual deviation from their periodicity. For this purpose, quasiperiodic nanoribbons were built, which lie between periodic and disordered medium, distributing the domains of graphene and hBN in their supercells according to the Fibonacci, Thue-Morse and Double-Period sequences, which exhibit controlled growth from the periodic case. The results revealed a similar behavior for the three sequences analysed. In the periodic case, there is a non-monotonic behavior of the thermal conductivity with the superlattice period, which is a consequence of the crossover from the coherent (phonons wave-like) to incoherent (phonons particle-like) thermal transport regime, as has been reported in the literature. However, as the translation symmetry of the nanoribbons degrade with the quasiperiodicity of the supercell, the coherent thermal transport regime is gradually suppressed due to the diffuse scattering of phonons in different length scales. This allows to reduce its thermal conductivity in a controlled manner, being able to provide a value up to 60 % smaller than the thermal conductivity of its periodic counterpart. This finding opens a new horizon for the control of nanoscale heat transport and presents a valuable strategy for the development of new thermoelectric materials