Heat Transfer across Van der Waals Atomic Interaction at Solid Interface

Thermal energy transfer at the interface by the atomic interactions is the most fundamental energy transport mechanism for transferring thermal energy between materials. Recent advances in nano and atomic technology have made the size of device structures reach from several nanometers to several angstroms. As a result, heat transfer through the interface is more important than heat transfer within the material. Because of this importance, various studies on heat transfer through the interface have been conducted, but since the development of a device that can precisely control atomic interaction and measure heat transfer is very challenging, accurate verification of interfacial heat transfer through atomic interaction has not been achieved. Here, we developed and utilized scanning thermal probes to measure interfacial heat transfer while controlling van der Waals(vdW) energy at nanometer contacts. In particular, the atomic-milling method was used to fabricate the tip of the probe with an atomically flat surface and the relationship between vdW interaction and interfacial heat transfer was investigated proceeding the milling. Based on the experimental results obtained from the four samples, it was confirmed that high-frequency phonons modes were suppressed according to the binding energy inside each material and the vdW interaction energy. We also use the lattice-dynamical calculation and Molecular Dynamics(MD) simulation to validate the approach of suppression effects due to vdW interactions. Finally, we present the advanced approach that applies the vdW interaction energy of the interface to the DMM. This study provides insight into the theory of heat transfer through interface made of vdW interactions, and presents a milestone for considering interactions between materials for the development of various devices such as 2D materials and self-assembled monolayers.