Plateau effect in the thermal conductivity of solid hydrogen with neon impurity

Abstract

The thermal conductivity of solid hydrogen with 1-2 ppm Ne impurity was investigated in the temperature range 1.5-10 K on samples grown from the liquid phase at various growth rates. The result differ qualitatively from those obtained on samples grown from the gas phase: the thermal conductivity curve exhibited a dip in a broad plateau. The relaxation model is suggested to explain the effect supposedly due to linear impurity structures, arranged on dislocation lines. A comparison with the case of isolated neon atoms homogeneous distributed in the solid hydrogen is made. PACS: 67.80.Gb Thermal properties; 65.40.-b Thermal properties of crystalline solids.

Effects of site-occupation disorder on the low-temperature thermal conductivity of molecular crystals

“…In fact, samples of para-H 2 containing minute amounts of a Ne impurity [46], exhibit a noticeable plateau between 2 K and 5 K as also does a CH 4 -CD 4 solid solution. The appearance of such a glassy feature is there explained as arising from the enhancement of the interaction of rotations with crystal phonons since the rotational constant B r for CD 4 comes to be one half of that of CH 4 which amounts to 158 GHz.…”