次近邻跃迁对石墨烯纳米带输运性质的影响

Effect of next-nearest neighbor hopping on the transport properties of graphene nanoribbons

根据紧束缚模型,利用格林函数的方法,将次近邻跃迁考虑在内,研究了扶手椅型石墨烯纳米带的输运性质.通过数值计算,给出了不同尺寸和不同次近邻跃迁能下系统的能量-电导和电流-电压特征曲线.结果表明,次近邻跃迁对扶手椅型石墨烯纳米带的输运性质有显著的影响.它破坏了电导共振峰关于能量的对称分布,增强了系统的导电性,减小了电子导电偏压阈值,加速了系统输运性能由半导体向导体转变.次近邻跃迁能和石墨烯纳米带的尺寸越大,这种影响越明显.

Based on tight-binding model, using the Green function method, the transport properties of armchair graphene nanoribbons taking into account the next-nearest neighbor hopping are studied. By numerical calculations, the conductance-energy and current-voltage characteristics for different next-nearest hopping energies and sizes are given. The results show that the next-nearest neighbor hopping has significant effect on the transport properties of graphene nanoribbons. It breaks the symmetrical conductance resonance peaks distribution about energy, enhances the conductivity of the system, decreases the threshold bias voltage of electron conduction, and accelerates the transmission of transport properties of the system from the semiconducting to the conducting material. The bigger next-nearest hopping energy and larger size of graphene nanoribbons, the more significant of this effect.