Abanin D A, Levitov L S
Department of Physics, Center for Materials Sciences and Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
Science. 2007 Aug 3;317(5838):641-3. doi: 10.1126/science.1144672. Epub 2007 Jun 28.
Recent experimental work on locally gated graphene layers resulting in p-n junctions has revealed the quantum Hall effect in their transport behavior. We explain the observed conductance quantization, which is fractional in the bipolar regime and an integer in the unipolar regime, in terms of quantum Hall edge modes propagating along and across the p-n interface. In the bipolar regime, the electron and hole modes can mix at the p-n boundary, leading to current partition and quantized shot-noise plateaus similar to those of conductance, whereas in the unipolar regime transport is noiseless. These quantum Hall phenomena reflect the massless Dirac character of charge carriers in graphene, with particle/hole interplay manifest in mode mixing and noise in the bipolar regime.
近期关于形成p-n结的局部栅控石墨烯层的实验工作揭示了其输运行为中的量子霍尔效应。我们根据沿p-n界面传播以及穿过p-n界面的量子霍尔边缘模式，解释了所观察到的电导量子化现象，即在双极区为分数形式，在单极区为整数形式。在双极区，电子和空穴模式可在p-n边界处混合，导致电流分配以及与电导类似的量子化散粒噪声平台，而在单极区输运是无噪声的。这些量子霍尔现象反映了石墨烯中电荷载流子的无质量狄拉克特性，粒子/空穴相互作用表现为双极区的模式混合和噪声。
