Variations of Acoustic and Diffuse Mismatch Models in Predicting Thermal-Boundary Resistance

Solid-solid thermal-boundary resistance plays an important role in determining heat flow, in both cryogenic and room-temperature applications. The acoustic mismatch model (AMM) and the diffuse mismatch model (DMM) have traditionally been used to predict the thermal boundary resistance R b across the interface of two adjoining materials at temperatures well below the Debye temperatures of the materials in question. Both the AMM and DMM use the Debye density of states (DOS) in both contacting solids. Here, the use of a measured DOS is made in conjunction with the DMM. This shows an improvement in the prediction of R b relative to that based on the Debye DOS. Another approach considered is to predict R b from measured specific heat per unit volume C data. The measured C automatically includes the effect of temperature on the DOS. This leads to a marginal improvement in R b above that predicted when using the measured DOS. The AMM describes the thermal transport at a solid-solid interface below a few Kelvin quite accurately