  Recently, massive efforts have been done on controlling thermal transport via
coherent phonons in the various periodic nanostructures. However, the intrinsic
lattice difference between the constituent materials inevitably generates the
disorder at the interfaces, thus limiting the opportunity of directly observing
the coherent phonon transport. Here, we investigate the controllability and
visualization of the coherent phonon transport in a periodic MoS2/MoSe2 arrayed
heterostructure with minimum lattice mismatching using non-equilibrium
molecular dynamics simulation. It is found that the coherent phonon transport
can be destroyed and rebuilt through adjusting the density of MoSe2 nanodot
arrays. The phonon localization induced by the destruction of correlation is
visualized based on the spatial energy distribution and anharmonic analysis.
Furthermore, the eigen vector diagrams provide a distinct visualization of the
localized phonon modes. Besides, the correlation of phonon can be rebuilt by
reducing the period length, which is verified by the enhanced group velocities
extracted from phonon dispersion curves. Interestingly, the crossover from
incoherent to coherent phonon transport is directly observed by the spatial
energy distributions and the spectral phonon transmission coefficients.
Finally, the size and temperature dependence of thermal conductivity are also
discussed. This study of the phonon coherence and its visualizing manipulation
on thermal conductivity will be beneficial to fine heat control and management
in the real applications.
