  Crystal phase engineering gives access to new types of superlattices where,
rather than different materials, different crystal phases of the same material
are juxtaposed. Here, by means of atomistic nonequilibrium molecular dynamics
calculations, we study to what extent these periodic systems can be used to
alter phonon transport, similarly to what has been predicted and observed in
conventional superlattices based on heterointerfaces. We focus on twin
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.
