Relationship of thermal boundary conductance to structure from an analytical model plus molecular dynamics simulations

Thermal boundary resistance dominates the overall resistance of nanosystems. This effect can be utilized to improve the figure of merit of thermoelectric materials. It is also a concern for thermal failures in microelectronic devices. The interfacial resistance depends sensitively on many interrelated structural details including material properties of the two layers, the system dimensions, the interfacial morphology, and the defect concentrations near the interface. The lack of an analytical understanding of these dependencies has been a major hurdle for a science-based design of optimum systems on a nanoscale. Here we have combined an analytical model with extensive, highly converged direct-method molecular dynamics simulations to derive analytical relationships between interfacial thermal boundary resistance and structural features. We discover that thermal boundary resistance linearly decreases with total interfacial area that can be modified by interfacial roughening. This finding is further elucidated using wave-packet analysis and local density of state calculations.