Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IA 52242, USA.
J Phys Condens Matter. 2013 Jan 30;25(4):045303. doi: 10.1088/0953-8984/25/4/045303. Epub 2012 Dec 20.
We report the plasmon dispersion characteristics of intrinsic and extrinsic armchair graphene nanoribbons of atomic width N = 5 using a p(z)-orbital tight binding model with third-nearest-neighbor (3nn) coupling. The hopping parameters are obtained by fitting the 3nn dispersions to those of an extended Hückel theory. The resultant massive Dirac fermion system has a band gap E(g) ≈ 64 meV. The extrinsic plasmon dispersion relation is found to asymptotically approach a universal dispersion curve as the chemical potential μ increases, whereas the intrinsic plasmon dispersion relation is found to have both energy and momentum thresholds. We also report an analytical model for the extrinsic plasmon group velocity in the q → 0 limit.
我们使用具有第三近邻（3nn）耦合的 p(z)-轨道紧束缚模型报告了原子宽度 N = 5 的本征和外禀扶手椅石墨烯纳米带的等离子体色散特性。通过将 3nn 色散拟合到扩展 Hückel 理论的色散，得到了跃迁参数。所得的大量狄拉克费米子系统具有带隙 E(g)≈64 meV。随着化学势 μ 的增加，外禀等离子体色散关系被发现渐近地接近一个普遍的色散曲线，而本征等离子体色散关系被发现具有能量和动量阈值。我们还报告了外禀等离子体群速度在 q→0 极限下的分析模型。
