The Thermal Conductivity Plateau in Disordered Systems
The thermal conductivity of disordered substances exhibits a region of weak temperature dependence known as the “plateau” . It occurs in glasses in a temperature range typically between 1 and 20 K. At much lower temperatures, the thermal conductivity is governed by the resonant scattering of thermal phonons from tunneling systems and follows a T2 power law. Above the plateau the temperature dependence is roughly linear in T. Explanations offered for the occurrence of a plateau include: phonon scattering by enhanced densities of tunneling systems , elastic scattering by density fluctuations , dimensional crossover of the vibrational density of states , and weak localization of phonons . As yet there has been no convincing description of this phenomenon.
KeywordsPorosity Epoxy pOlystyrene PMMA
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