We demonstrate the coherent transport of thermal energy in superlattices by
introducing a microscopic definition of the phonon coherence length. We
demonstrate how to distinguish a coherent transport regime from diffuse
interface scattering and discuss how these can be specifically controlled by
several physical parameters. Our approach provides a convenient framework for
the interpretation of previous experiments and thermal conductivity
calculations and paves the way for the design of a new class of thermal
interface materials.Comment: 5 pages, 6 figures, 1 tables The method which is described is too
sensitive to numerical noise. A new method has been developed and published
in http://journals.aps.org/prb/abstract/10.1103/PhysRevB.90.01430