Coherent and incoherent phonon thermal transport in group-III nitride monolayer superlattices with Tersoff type interatomic potential

The existence of a crossover from coherent to incoherent phonon transport for different monolayer superlattices such as h-BN/h-AlN, h-BN/h-GaN, h-AlN/h-GaN, and h-BN/h-AlN/h-GaN using large-scale non-equilibrium molecular dynamics simulations is unveiled. In this context, the lattice thermal conductivities of considered superlattice structures are obtained for varying period lengths, sample lengths, and temperatures. It is predicted that the thermal conductivities of superlattice structures can be lowered even up to 99% than that of their pristine counterparts. Also, it is revealed that a minimum thermal conductivity resulting from the competition between coherent, wave-like, and incoherent, particle-like, phonon transport can be achieved by altering the period length for all the superlattice structures. Moreover, it is observed that the thermal conductivity minimum at higher temperatures compared to low temperatures occurs at shorter period lengths for binary superlattices, and the minimum depths decrease with increasing temperature. Results point out that group-III nitride superlattices can be considered as an alternative option in controlling the heat flow for thermal management and thermoelectric device applications.