Transport Relaxation Time for Phonon-Impurity Scattering

✍ Scribed by V. I. Altukhov; G. S. Zavt

• Publisher: John Wiley and Sons
• Year: 1972
• Tongue: English
• Weight: 525 KB
• Volume: 54
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2220540105

✦ Synopsis

Abstract

Starting from the Kubo formula the thermal conductivity is expressed by the two‐phonon Green's function. The latter is calculated for a cubic lattice containing a small fraction of impurities with taking into account the change of force constants. It is shown that the procedure of the configurational average introduces a correlated motion of two phonons which is described by the vertex correction. This correction appears to be essential if the impurity generates at least two resonant modes with close frequencies but with opposite parity. In this case the scattering cross‐section is decreased by the vertex correction. The correlation in the phonon motion is expected to be essential in KI: Ag.