Two-level tunnelling model description of thermal conductivity for Cu_χSn_1-χ metallic glasses at low temperature

The two level tunnelling model is applied to analyze recent experimental data on low temperature thermal conductivity of Cu_χSn_1-χ metallic glasses. An extra scattering mechanism due to Rayleigh is introduced to describe three characteristic regions of conductivity. Model parameters are determined using least-squares fitting procedure. Results derived from the parameters allow one to predict several interesting low temperature properties of metallic glasses in particular the characteristic plateau of conductivity. Theoretical results are also compared and contrasted with those of other metallic and non-metallic systems, and both common and uncommon features that exist between them are discussed.