Coherent transport in graphene nanoconstrictions
Coherent transport in graphene nanoconstrictions
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DOI：
10.1103/physrevb.74.195417
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发表时间：
2006-08
影响因子：
3.7
通讯作者：
F. Mũnoz-Rojas;David Jacob;J. Fernández-Rossier;Juan Jose Palacios
中科院分区：
文献类型：
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作者：
F. Mũnoz-Rojas;David Jacob;J. Fernández-Rossier;Juan Jose Palacios
我们研究了结构纳米收缩对理想锯齿形边缘无限长石墨烯带的相干传输特性的影响。采用标准单轨道紧束缚模型计算电子结构，并采用Landauer公式获得线性电导。我们发现，由于零偏置电流是在带材的主体中承载的，因此对于各种收缩几何形状和边缘缺陷来说，这是非常稳健的。相反，一旦从样品中去除单个原子，零偏置电导与栅极电压的曲线就会偏离理想情况的 2n +1 e 2 /h 阶梯。我们还发现，楔形收缩可以呈现完全局域于接近费米能量的收缩中的非导电态。讨论了这些局域态对于石墨烯中量子点形成的兴趣。
We study the effect of a structural nanoconstriction on the coherent transport properties of otherwise ideal zigzag-edged infinitely long graphene ribbons. The electronic structure is calculated with the standard oneorbital tight-binding model and the linear conductance is obtained using the Landauer formula. We find that, since the zero-bias current is carried in the bulk of the ribbon, this is very robust with respect to a variety of constriction geometries and edge defects. In contrast, the curve of zero-bias conductance versus gate voltage departs from the 2n +1 e 2 /h staircase of the ideal case as soon as a single atom is removed from the sample. We also find that wedge-shaped constrictions can present nonconducting states fully localized in the constriction close to the Fermi energy. The interest of these localized states in regards to the formation of quantum dots in graphene is discussed.