Thermal conductivity of Xe clathrate hydrate at low temperatures

• DOI: 10.1103/physrevb.73.064203
• Publication Date: 2006-02-07T18:10:24Z
• Authors: A. I. Krivchikov; B. Ya. Gorodilov; O. A. Korolyuk; V. G. Manzhelii; O. O. Romantsova; H. Conrad; W. Press; J. S. Tse; D. D. Klug
• Keywords: Clathrate hydrate

The effective thermal conductivity of the powder samples xenon hydrate was measured in interval $2--170\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ using steady-state method. homogeneous Xe clathrate estimated from an empirical expression. applicability formula checked by comparing two with different grain size and porosity. temperature dependence $\ensuremath{\kappa}(T)\ensuremath{\sim}{T}^{\phantom{\rule{0.2em}{0ex}}n}$ is divided into four distinct regimes (I--IV) $n$. In $55--97\phantom{\rule{0.3em}{0ex}}\mathrm{K}$ (III) behavior $\ensuremath{\kappa}(T)$ shows anomaly, where decreases almost 50% as increases. This observation attributed to resonant scattering coupling lattice ``rattling'' motions atom dominates resistivity at high temperature. Since observed vibrational energy small cages $\ensuremath{\sim}4\phantom{\rule{0.3em}{0ex}}\mathrm{meV}$ (or $\ensuremath{\approx}46\phantom{\rule{0.3em}{0ex}}\mathrm{K}$) contribution expected decrease comparable low regime (regimes I II) found follow prediction soft-potential model. data on conductivities several gas hydrates are compared.