Role of Three-Phonon Normal Processes in the Phonon Conductivity of an Insulator

概要

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In the present work the role of three-phonon normal processes is studied in the framework of Callaway's theory of Phonon conductivity of an insulator under the conditions τ^<-1>_N>τ^<-1>_R, τ^<-1>_N<τ^<-1>_R and τ^<-1>_N≪τ^<-1>_R where τ^<-1>_R=τ^<-1>_B+τ^<-1>_<pt>+τ^<-1>_U. Use also made of a parameter 'a', which is a measure of the relative strengths of normal and Umklapp processes and is equal to τ^<-1>_N/τ^<-1>_U in Callaway's model. It is shown that for τ^<-1>_N≪τ^<-1>_R and 'a' approaching 10^<-3> Callaway's model gives good description of phonon conductivity of Ge in the temperature range 2 to 100 K. For τ^<-1>_N≫τ^<-1>_ R Callaway's theory gives not only the smaller values of phonon conductivity but also leads to wrong temperature dependence in the range 20-100 K.
社団法人日本物理学会の論文
1972-05-05