石墨的拉曼张量:G、D和D′声子的对称性

Raman tensor of graphite:Symmetry of G,D and D′phonons

自石墨的拉曼光谱在1970年被首次记录以来,其拉曼特征峰(G、D和D′峰)背后的物理起源一直是人们争论的焦点.目前,人们普遍认为G峰对应于拉曼活性E_(2g2)模式,D和D′峰则是与缺陷有关的无序诱发峰.然而,到目前为止,这些石墨拉曼峰所对应的声子对称性,还缺乏细致的研究与直接的实验证据.在这里,我们利用角分辨偏振拉曼光谱对这些重要方面进行了阐述.结果表明,D、D′峰的实验拉曼强度与G峰的偏振角关系相似.结合拉曼张量分析和双共振机制,我们进一步了解了D′和D峰的声子对称性.我们的工作为石墨声子对称性提供了可靠的实验证据和合理的解释.

Graphite is a natural highly-anisotropic layered material formed by stacking in the direction perpendicular to two-dimensional(2D)graphene monolayers.As an anisotropic material,graphite is characterized by its extraordinary optical response[1].For example,the Raman scattering effect of graphite is both complex and intriguing to be an important window for peeping through its physical properties[1].