T→0 K下一维绝缘铁磁链的磁振子寿命

The Magnon Lifetime of One Dimensional Insulated Ferromagnetic Chain at T→0 K

在一维绝缘铁磁链系统基础上建立了一个磁振子-声子相互作用模型.利用格林函数方法研究了T→0 K时磁振子-声子相互作用下的一维绝缘铁磁链的磁振子衰减,计算了在布里渊区的磁振子衰减-Im∑*(1)(k)曲线.发现在布里渊区边界区域磁振子衰减最明显.也讨论了各项参数的变化对磁振子衰减的影响.根据关系式-Im∑*(1)(k)=/(2τ)可以对磁振子寿命进行判断.

A magnon-phonon interaction model is built in one dimensional insulated ferromagnetic chain. By using Matsubara Green function theory, we have studied the magnon damping -Im∑^＊（1）（k）, and calculated the magnon damping -Im∑^＊（1）（k） curve in the Brillouin Zone for different parameters in the system. It is concluded that at the boundary of Brillouin Zone there is a strong magnon damping. But the magnon damping is very small on Zone of small wave vectors, and magnon damping has maximal at the boundary of Brillouin Zone. According to Expression -Im∑^＊（1）（k）= h/（2τ） ,the magnon lifetime can be discussed.