含有格点势的一维Fibonacci链热传导性质的研究

Heat conduction in one-dimensional Fibonacci chain with on-site potential

用传输矩阵的方法,研究了格点势(on-site势)对一维Fibonacci链的热传导性质(透射系数、Lyapunov指数及热导率κ)的影响.研究结果表明:当固定原子质量比和力作用常数比时,随着格点势的增大,低频区域的透射系数减小,对应的Lyapunov指数增大,透射谱向高频方向移动.同时,格点势越大,同样大小的体系对应的κ越小,当格点势足够大时,κ会趋近零.在热导率κ对振动频率ω2作图中,κ呈现台阶式缓慢上升的趋势,且在高频端趋于某一稳定值。

By making use of the method of transfer matrix,we study the behaviors of heat conduction in one-dimensional Fibonacci chain under the influence of on-site potential（including transmission coefficient,Lyapunov coefficient and heat conduction）.The results show that,with the on-site potential increasing while fixing the ratios of atom mass and force constant,the transmission coefficient of the low-frequency region decreases,and the corresponding Lyapunov coefficient increases,and the transmission spectrum moves to the higher frequency region.Meanwhile,with the increasing of on-site potential,the heat conductivity of the system decreases.When the on-site potential is large enough,the thermal conductivity of the system will tend to zero.In the curve of κ-ω2,the thermal conductivity shows a slowly increasing trend in steps,and tends to a certain value in the high-frequency region.