采用紧束缚方法计算了石墨烯的价带(π)和导带(π∗)，考虑了非正交基矢下重叠矩阵效应，重叠积分参量s越小，导带越靠近费米面，而价带越远离费米面.在重叠积分参量s≤0.1时，基本保持了原子在实际空间中重叠所引起的能带的改变，太大(s=0.4)则会导致物理上失效.计算了石墨烯的能态密度，在费米面ε=0处(对应Dirac点)的能态密度为零，并且在Dirac点附近呈线性变化.%By employing the tight-binding method, we calculated the valence band ( π) and the conduction band ( π∗) of graphene. Under the consideration of the overlap matrix effect in the case of nonorthogonal ba-sis, when the overlap integral parameter s decreases, the conduction band gets closer to the Fermi surface and the valence band becomes further to the Fermi surface. When the parameter s is smaller than 0. 1, it almost keeps the change of energy band induced by the atoms in real space. If s becomes larger, such as, s=0. 4, the energy band is totally distorted and leads to the unphysical phenomenon. Moreover, we have calculated the den-sity of states of graphene. On the Fermi surface (Dirac point), the density of states is zero, and we also ob-served a linear variation around the Dirac point.
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