Resonant surface scattering and dislocation flutter explain Kapitza resistance at a solid/solid He-4 interface

摘要

In this report we investigate the Kapitza resistance R-K at an interface between a classical solid and a He-4 quantum crystal, as a function of temperature. We provide a premise for R-K based on a combination of two separate mechanisms which occur simultaneously. Owing to the fact that the phonon wavelengths in solid He-4 and in the superfluid are of the same order of magnitude, we infer that one mechanism is due to resonant scattering of phonons by nanoscale surface roughness as predicted by Adamenko and Fuks(1) for solid/superfluid interfaces. The other mechanism involves the interaction of thermal phonons with mobile vibrating dislocations within solid He-4. The present analysis demonstrates the plausibility of these two mechanisms in solving the long outstanding problem of the Kapitza resistance anomaly of solid He-4 in contact with copper for temperatures ranging from 0.4 to 2 K.