Visualizing atomic-scale negative differential resistance in bilayer graphene.
Visualizing atomic-scale negative differential resistance in bilayer graphene.
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DOI：
10.1103/physrevlett.110.036804
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发表时间：
2013-01
影响因子：
8.6
通讯作者：
K. Kim;Tae-Hwan Kim;A. Walter;T. Seyller;H. Yeom;E. Rotenberg;A. Bostwick
中科院分区：
文献类型：
--
作者：
K. Kim;Tae-Hwan Kim;A. Walter;T. Seyller;H. Yeom;E. Rotenberg;A. Bostwick
我们使用扫描隧道显微镜研究了碳化硅上双层石墨烯的原子尺度隧道特性。高分辨率隧道光谱揭示了狄拉克能量下意想不到的负微分电阻（NDR），该电阻在双层石墨烯的单个晶胞内空间变化。 NDR 的起源可以通过横向电场下双层石墨烯电子谱中出现的两个近带隙范霍夫奇点来解释，它们强烈局域于不同层的两个亚晶格上。此外，发现隧道接触附近的缺陷通过电子干扰对 NDR 产生强烈影响。我们的结果提供了对双层石墨烯中量子隧道效应的原子级理解，并为基于石墨烯的隧道器件迈出了有用的一步。
We investigate the atomic-scale tunneling characteristics of bilayer graphene on silicon carbide using the scanning tunneling microscopy. The high-resolution tunneling spectroscopy reveals an unexpected negative differential resistance (NDR) at the Dirac energy, which spatially varies within the single unit cell of bilayer graphene. The origin of NDR is explained by two near-gap van Hove singularities emerging in the electronic spectrum of bilayer graphene under a transverse electric field, which are strongly localized on two sublattices in different layers. Furthermore, defects near the tunneling contact are found to strongly impact on NDR through the electron interference. Our result provides an atomic-level understanding of quantum tunneling in bilayer graphene, and constitutes a useful step towards graphene-based tunneling devices.