Thermal Conductivity of Selenium at Low Temperatures

Measurements are reported of the thermal conductivity of glassy selenium and polycrystalline metallic (hexagonal) selenium at temperatures from 2^∘{} to above 100^∘{}K. At the higher temperatures, the heat conductivity, λ, for the glassy solid is about 1 mw/cm deg. If we write λ≈1/3lCv, then l, the mean free path, is of the order of the interatomic distance. On the other hand, for the high-purity metallic samples, λ5/T w/cm deg. At low temperatures in metallic selenium, λ varies approximately as T², while in the glassy modification λ behaves in a similar fashion to that expected from earlier observations on soft glass and Pyrex.