LAUSR

We report an approach to modulate thermal conduction that utilizes phonon coupling in layered nanostructures. While phonon coupling has been used previously to enhance thermal transport of an embedded layer in a tri-layer structure, the impact of coupling on cladding layers has remained unclear. Here, we develop a methodology to quantitatively evaluate the impact of phonon coupling on each layer in a tri-layer structure. We uncover that the underlying phonon-injection mechanism behind thermal conductivity enhancement can also be leveraged to reduce the thermal conductivity of an embedded silicon thin-film below its free-standing value. We evaluate the dependence of resultant thermal conductivity modulations on structural parameters and find that they are critically dependent on layer spacings and interface properties. We also extend the tri-layer transport analysis to bi-layer structures and report how phonon coupling leads to analogous thermal conductivity modulations. The results of this work open new a...