Thermal Conductivity, Viscosity and Phonon Decay in 4 He Films

For superfluid 4 He films at low temperatures, we evaluated the thermal conductivity and viscosity in consideration of the scattering of phonons by rotons. These coefficients increase almost exponentially towards 0 K starting around 0.9 K. The rate for spontaneous phonon decay through 3pp is found t...

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Bibliographic Details
Published in:Japanese Journal of Applied Physics 1987-01, Vol.26 (S3-1), p.295
Main Authors: Um, C. I., Jun, C. W., Kahng, W. H., Isihara, A.
Format: Article
Language:English
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Summary:For superfluid 4 He films at low temperatures, we evaluated the thermal conductivity and viscosity in consideration of the scattering of phonons by rotons. These coefficients increase almost exponentially towards 0 K starting around 0.9 K. The rate for spontaneous phonon decay through 3pp is found to increase as q 3 first, reaches a maximum, and then drops to zero at the threshold wave number q * . The decay rate decreases with pressure and increases with film coverage.
ISSN:0021-4922
1347-4065
DOI:10.7567/JJAPS.26S3.295