低温下二维绝缘铁磁体的磁振子软化

在二维正方绝缘铁磁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 究了磁振子-声子相互作用下的二维绝缘铁磁体的磁振子谱, 计算了布里渊区的主要对称点 线上的磁振子色散曲线.发现在布里渊区边界区域磁振子谱的软化和磁振子谱线增宽最明显. 比较了纵向声子与横向声子对磁振子谱的软化与磁振子谱线增宽的影响，也讨论了各项参数 的变化对磁振子谱的软化与磁振子谱线增宽的影响. 关键词： 磁振子-声子相互作用 磁振子软化 铁磁体 磁振子谱线增宽

The softening of magnon of two-dimensional insulating ferromagnets at low temperatures

A magnon-phonon interaction model is applied to two_dimensional insulating ferro magnets. By using Matsubara Green function theory, we have studied the magonon spectrum, and calculated the magnon dispersion curve on the main symmetric point and line in the Brillouin Zone for different parameters of the system. It is con cluded that at the boundary of Brillouin Zone there is a strong broadening in th e magnon linewidth and softening. The influences of longitudinal phonon and tran sverse phonon on the softening and broadening in the magnon linewidth are compar ed, and the influences of the parameters are also illustrated.