Temperature and volume dependence of the thermal conductivity of solid neon

Abstract

The thermal conductivity $\ensuremath{\kappa}$ of solid natural neon has been measured by the linear-flow method for specimens isobarically frozen from the dense-fluid phase within a high-strength steel cell. By crossing the fusion curve at several different pressures to as high as 7 \ifmmode\times\else\texttimes\fi{} ${10}^{3}$ bars, crystalline samples with molar volumes between 11.16 and 13.35 ${\mathrm{cm}}^{3}$/mole were grown, and for each the isochoric variation of $\ensuremath{\kappa}$ vs $T$ was determined at a set of temperatures in the experimentally accessible range between 5 and 40 K. The large magnitude of $\ensuremath{\kappa}$ and reproducibility of the results demonstrate that the present method of preparation and manipulation of solid neon consistently yields good-quality specimens. An analysis utilizing the zero-degree limit of the Debye temperature ${\ensuremath{\Theta}}_{0}$ to account for all volume dependence indicates that the array of data, when expressed in terms of the resistive mean free path, may be rendered into a single function of the inverse reduced temperature $\frac{{\ensuremath{\Theta}}_{0}}{T}$. The exponential variation of this common curve over more than 2 orders of magnitude is characteristic of three-phonon umklapp scattering and thereby gives support to Peierls's model of heat transport in dielectric crystals. More recent first-principles theoretical calculations are in qualitative agreement with experiment but yield conductivities somewhat below the observed values.