石墨片的拉伸形变研究

Stretching deformation of graphene

利用静力学方法研究了受外力作用下锯齿边和扶手边石墨片的形变规律。给出了键角、键长和杂化轨道的s-轨道成份和p-轨道成份随外力的变化关系。在锯齿型边的石墨片中以外力为对称轴的两个杂化轨道其s-轨道成份随外力减小,而与外力共轴的轨道其s-轨道成份是增加的。对p-轨道来说,以外力为对称轴的p_x-轨道成份大小随外力增加,而与外力共轴的恰减小,p_y^-和p_z^-轨道成份不变;扶手型边的结果正好与锯齿型边相反。结果表明:一个较小的外力就能引起石墨片的较大形变,从而能够调控石墨片的带隙。

The stretching deformation of graphene with zigzag and armchair shaped edges respectively is studied by means of static mechanics. The relations between a tensile force and the bond angle, bond length, s-orbital and p-orbital components, respectively, are given. For zigzag shaped edges, the s-orbital components of two hybrid orbitals symmetrical to the tensile force decrease with the force and one coaxial to the force increases with. The case of p_x-orbital components is just opposite to that of s-orbital components and p_y^- and p_z^- orbital components are unchanged. For armchair shaped edges, the results are opposite to that of zigzag edges. Studies show that a small tensile force can give rise to large deformation of graphene and then control its energy gap.