二维三角晶格的Peierls相变前后的声子色散曲面的研究

利用晶格动力学理论计算了二维三角晶格的Peierls相变前后的声子能谱。并且在第一布里渊区绘制了声子色散曲面。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。二维三角晶格的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与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。

Study of curved surfaces of phonon dispersion in trigonal lattice of two-dimensional pre- and after Peierls phase transition

We have calculated the phonon spectrum of trigonal lattice of two-dimensional pre- and after Peierls phase transition applying lattice dynamics in this article. We have also drawn the curved surfaces of phonon dispersion in the first Brillonin Zone,compared with phonon spectrum of trigonal lattice of two-dimensional pre- and after 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,and there are two pieces acoustic phonons and two pieces optical phonons after Peierls transition,and the two pieces will not crosse,two optical phonons changed gently in the axis of k y.