The effect of disorder on the valley-dependent transport in zigzag graphene nanoribbons
The effect of disorder on the valley-dependent transport in zigzag graphene nanoribbons
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DOI：
10.1063/1.3599930
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发表时间：
2011-06
影响因子：
3.2
通讯作者：
Ying-Tao Zhang;Qing-feng Sun;Xin-cheng Xie
中科院分区：
文献类型：
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作者：
Ying-Tao Zhang;Qing-feng Sun;Xin-cheng Xie
我们研究了电子在锯齿形石墨烯纳米管中的输运，该石墨烯纳米管具有交错的亚晶格势和一定的非对称边界势。利用紧束缚模型，联合收割机非平衡绿色函数理论和Landauer-Buttiker公式，计算了体系的能带结构、电导和电导涨落。我们发现，一个能隙打开由于反转对称性破缺的交错的亚晶格势。通过进一步调整边界势，实现了无带隙的谷依赖边缘态，其中在给定边界上具有不同谷的载流子沿相反方向传播。此外，我们还研究了长程无序对谷依赖边缘态输运性质的影响。结果表明，对于低密度无序，在较宽的无序强度范围内，边缘态贡献的电导平台4 e2/h都能很好地保持，表明了谷依赖的稳定性。
We investigate the electron transport through a zigzag graphene nanoribbon with a staggered sublattice potential and a certain asymmetric boundary potential. By using the tight binding model to combine with the nonequilibrium Green’s function theory and the Landauer–Buttiker formalism, the energy band structure, conductance, and conductance fluctuation are calculated. We find that an energy gap opens up due to the inversion symmetry breaking by the staggered sublattice potential. By further tuning the boundary potential, the gapless valley-dependent edge states are achieved in which the carriers with the different valleys on a given boundary propagate in opposite directions. Furthermore, we study the effect of long range disorder on the transport properties of the valley-dependent edge states. The results show that the conductance plateau 4e2/h contributed by the edge states can be maintained well in a broad range of disorder strength for low-density disorder, indicating the robustness of the valley-depen...