Phonon Transport in GaAs and InAs Twinning Superlattices

Crystal phase engineering gives access to new types of periodic nanostructures, such as the so-called twinning superlattices, where the motif of the superlattice is determined by a periodic rotation of the crystal. Here, by means of atomistic nonequilibrium molecular dynamics calculations, we study to what extent these periodic systems can be used to alter phonon transport in a controlled way, similar to what has been predicted and observed in conventional superlattices based on heterointerfaces. We focus on twinning superlattices in GaAs and InAs and highlight the existence of two different transport regimes: in one, each interface behaves like an independent scatterer; in the other, a segment with a sufficiently large number of closely spaced interfaces is seen by propagating phonons as a metamaterial with its own thermal properties. In this second scenario, we distinguish the case where the phonon mean free path is smaller or larger than the superlattice segment, pointing out a different dependence of the thermal resistance with the number of interfaces.We acknowledge financial support by the Agencia Estatal de Investigación under grants FEDER-MAT2017-90024-P and RTI2018-097876-B-C21 (MCIU/AEI/FEDER, UE), the Severo Ochoa Centres of Excellence Program under grant CEX2019-000917-S, and the Generalitat de Catalunya under grant no. and 2017 SGR 1506. I.Z. acknowledges financial support by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 756365) and from the Swiss National Science Foundation (project grant no. 184942). We thank the Centro de Supercomputación de Galicia (CESGA) for the use of their computational resources. R.R. thanks Kai Nordlund for useful discussions.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe