Approach to Phonon Relaxation Time and Mean Free Path in Nonlinear Lattices

作     者：Yue Liu Dahai He 刘越;贺达海

作者机构：Department of PhysicsXiamen UniversityXiamen 361005China 

出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)

年 卷 期：2021年第38卷第4期

页      面：56-60页

核心收录：

学科分类：0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 

基　　金：the National Natural Science Foundation of China(Grant Nos.12075199 and 11675133) 

主　　题：phonon relaxation exponent 

摘      要：Based on the self-consistent phonon theory,the spectral energy density is calculated by the canonical transformation and the Fourier *** fitting the spectral energy density by the Lorentzian profile,the phonon frequency as well as the phonon relaxation time is obtained in one-dimensional nonlinear lattices,which is validated in the Fermi-Pasta-Ulam-β(FPU-β) and φ^(4) lattices at different *** phonon mean free path is then evaluated in terms of the phonon relaxation time and phonon group *** results show that,in the FPU-β lattice,the phonon mean free path as well as the phonon relaxation time displays divergent power-law *** divergent exponent coincides well with that derived from the Peierls-Boltzmann theory at weak anharmonic *** value of the divergent exponent expects a power-law divergent heat conductivity with system size,which violates Fourier’s *** the φ^(4) lattice,both the phonon relaxation time and mean free path are finite,which ensures normal heat conduction.