中国物理B ›› 2018, Vol. 27 ›› Issue (7): 76502-076502.doi: 10.1088/1674-1056/27/7/076502

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Thermal conductivity of systems with a gap in the phonon spectrum

E Salamatov   

  1. Udmurt Federal Research Center, Ural Branch of the Russian Academy of Sciences, Izhevsk 426067, Russia
  • 收稿日期:2017-11-07 修回日期:2018-04-17 出版日期:2018-07-05 发布日期:2018-07-05
  • 通讯作者: E Salamatov E-mail:esalama2i@gmail.com
  • 基金资助:
    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).

Thermal conductivity of systems with a gap in the phonon spectrum

E Salamatov   

  1. Udmurt Federal Research Center, Ural Branch of the Russian Academy of Sciences, Izhevsk 426067, Russia
  • Received:2017-11-07 Revised:2018-04-17 Online:2018-07-05 Published:2018-07-05
  • Contact: E Salamatov E-mail:esalama2i@gmail.com
  • Supported by:
    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).

摘要: An original theoretical model for describing the low-temperature thermal conductivity in systems with a region of forbidden values (a gap) in the phonon spectrum is proposed. The model is based on new experimental results on the temperature dependence of the phonon diffusion coefficient in nanoceramics and dielectric glasses which showed a similar anomalous behavior of the diffusion coefficient in these systems that may be described under the assumption of a gap in the phonon spectrum. In this paper, the role of the gap in low-temperature behavior of the thermal conductivity, κ (T), is analyzed. The plateau in the temperature dependence of the thermal conductivity is shown to correlate with the position and the width of the gap. The temperature dependence of thermal conductivity of such systems when changing the scattering parameters related to various mechanisms is studied. It is found that the umklapp process (U-processes) involving low-frequency short-wavelength phonons below the gap forms the behavior of the temperature dependence of thermal conductivity in the plateau region. A comparison of the calculated and experimental results shows considerable possibilities of the model in describing the low-temperature thermal conductivity in glass-like systems.

关键词: phononic band gap, phonon diffusion coefficient, thermal conductivity, glassy crystals

Abstract: An original theoretical model for describing the low-temperature thermal conductivity in systems with a region of forbidden values (a gap) in the phonon spectrum is proposed. The model is based on new experimental results on the temperature dependence of the phonon diffusion coefficient in nanoceramics and dielectric glasses which showed a similar anomalous behavior of the diffusion coefficient in these systems that may be described under the assumption of a gap in the phonon spectrum. In this paper, the role of the gap in low-temperature behavior of the thermal conductivity, κ (T), is analyzed. The plateau in the temperature dependence of the thermal conductivity is shown to correlate with the position and the width of the gap. The temperature dependence of thermal conductivity of such systems when changing the scattering parameters related to various mechanisms is studied. It is found that the umklapp process (U-processes) involving low-frequency short-wavelength phonons below the gap forms the behavior of the temperature dependence of thermal conductivity in the plateau region. A comparison of the calculated and experimental results shows considerable possibilities of the model in describing the low-temperature thermal conductivity in glass-like systems.

Key words: phononic band gap, phonon diffusion coefficient, thermal conductivity, glassy crystals

中图分类号:  (Thermal properties of amorphous solids and glasses: heat capacity, thermal expansion, etc.)

  • 65.60.+a
63.50.-x (Vibrational states in disordered systems) 61.43.Fs (Glasses)