紧束缚近似方法在计算石墨烯能带中的应用

通过引入紧束缚近似理论，使用Matlab计算了石墨烯的能带和π能带图．结果表明，考虑最近邻原子影响，在K—Г—M—K方向的全能带图中，观察到了能带的简并特性及能带间的跳跃，与其他方法（如第一原理）相符．在正交基矢下，π能带（价带和导带）具有完全的对称性，加入轨道重叠后（即非正交基矢），对称性被破坏，表现为价带靠近费米面，导带远离费米面，从能量的位移上可以发现，远离比靠近的趋势更为明显．

Application of. the Tight-binding Method in Calculating Graphene Band Structure

In this paper,the band structure and the n-band dispersion of graphene is are calculated by means of the nearest neighbor atom tight-binding method. The results show that in the K-P-M-K direction,the properties of the band structure are in agreement with what is calculated by the ab intio method, and the degeneracy and hopping phenomenon are observed. In the framework of orthogonal basis, the n-band structure is symmetric, but the addition of the orbital overlap breaks the symmetry, which means that the valence band goes close to the Fermi surface while the conduction band goes away from the Fermi surface. It can be observed from the energy shift that the latter tendency is more obvious than the former.