Thermal conductivity of systems with a gap in the phonon spectrum*

Project supported by the Ural Branch of the Russian Academy of Sciences, Russia (Grant No. 18-2-2-12), the Russian Foundation for Basic Research, Russia (Grant Nos. 16-07-00529 and 18-07-00191), and the Financing Program, Russia (Grant No. AAAA-A16-116021010082-8).
Salamatov E †
       

(color online) Phonon dispersion for the parameter values of (1) c = 0.2 and ε = 133, (2) c = 0.75 and ε = 60, and (3) c = 0.1 and ε = 33, which correspond the gap edges (in dimensionless units z = ω/ωD) of (1) z1 ≃ 0.05 and z2 ≃ 0.25, (2) z1 ≃ 0.075 and z2 ≃ 0.17, and (3) z1 ≃ 0.10 and z2 ≃ 0.2.