  Understanding thermal transport through nanoscale van der Waals interfaces is
vital for addressing thermal management challenges in nanoelectronic devices.
In this work, the interfacial thermal conductance (GCA) between copper
phthalocyanine (CuPc) nanoribbons is reported to be on the order of 10^5
Wm-2K-1 at 300 K, which is over two orders of magnitude lower than the value
predicted by molecular dynamics (MD) simulations for a perfectly smooth
interface between two parallelly aligned CuPc nanoribbons. Further MD
simulations and contact mechanics analysis reveal that surface roughness can
significantly reduce the adhesion energy and effective contact area between
CuPc nanoribbons, and thus result in an ultralow GCA. In addition, the adhesion
energy at the interface also depends on the stacking configuration of two CuPc
nanoribbons, which may also contribute to the observed ultralow GCA.
