Resonant surface scattering and dislocation flutter explain Kapitza resistance at a solid/solid 4He interface
Laboratoire d’Informatique pour la Mécanique et les Sciences de l’Ingénieur, LIMSI-CNRS, Université Paris-Saclay Orsay 91405, France
Received March 12, 2019, published online July 26, 2019
In this report we investigate the Kapitza resistance RK at an interface between a classical solid and a 4He quantum crystal, as a function of temperature. We provide a premise for RK based on a combination of two separate mechanisms which occur simultaneously. Owing to the fact that the phonon wavelengths in solid 4He 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  for solid/superfluid interfaces. The other mechanism involves the interaction of thermal phonons with mobile vibrating dislocations within solid 4He. The present analysis demonstrates the plausibility of these two mechanisms in solving the long outstanding problem of the Kapitza resistance anomaly of solid 4He in contact with copper for temperatures ranging from 0.4 to 2 K.