二维三角晶格的Peierls相变前后的声子色散曲线的研究

利用品格动力学理论计算了二维三角品格的Peimrls相变前后的声子能谱。并且在第一布里渊区绘制了主要的对称点、线上的声子色散曲线。通过对Peierls相变前后的声子能谱比较可知，随其对称性降低，声子能谱的简并度被破缺。二维三角品格的Peierls相变前只有两支声频支声子能谱，Peierls相变后有两支声频支声子能谱与两支光频支声子能谱，并且声频支声子能谱及光频支声子能谱不相交，两支光频支声子沿ky轴平缓地变化。

The study of phonon dispersion curves in trigonal lattice of two-dimension pre or behind Peierls phase transition

We have calculated the phonon spectrum of trigonal lattice of two-dimension pre or hehind Peierls phase transition using lattice dynamics in this article. We have also drawn the surfaces of phonon dispersion in the First Brillonin Zone and the curves of phonon dispersion with main symmetric point and line in the First Brillouin Zone. Compared phonon spectrum of trigonal lattice of two-dimension pre or hehind Peierls transition,we know phonon spectrum's consolidation have been split when its symmetry reduced. There are only two pieces of acoustic phonons before Peierls transition, there are two pieces acoustic phonons and two pieces optical phonons after Peierls transition,and they are not crossing each other, two optical phonons changed smoothly around the axis.