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arXiv 1707.09282cond-mat.mes-hall
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双层石墨烯中的静电诱导量子点接触

Electrostatically induced quantum point contact in bilayer graphene

Hiske Overweg, Hannah Eggimann, Xi Chen, Sergey Slizovskiy, Marius Eich, Riccardo Pisoni, Yongjin Lee, Peter Rickhaus, Kenji Watanabe, Takashi Taniguchi, Vladim… 展开作者

Hiske Overweg, Hannah Eggimann, Xi Chen, Sergey Slizovskiy, Marius Eich, Riccardo Pisoni, Yongjin Lee, Peter Rickhaus, Kenji Watanabe, Takashi Taniguchi, Vladimir Fal'ko, Thomas Ihn, Klaus Ensslin

摘要:

我们报道了在封装的双层石墨烯中制造静电限定的纳米结构,其漏电阻低于高达$R \sim 10~$ G $Ω$的耗尽栅。这超过了先前报告的值$R =~$ 10 - 100 k $Ω$。\cite{Zou2010,Yan2010,Zhu2016a}我们将这种改进归因于石墨背栅的使用。我们实现了两个分裂栅器件,它们定义了费米波长尺度上的电子通道。覆盖分裂栅极之间的间隙的沟道栅极改变沟道中的载流子密度。我们观察到$ΔG = 2~e^2/h$和$ΔG = 4~e^2/h$的器件依赖电导量子化。在量子化垂直于样品平面的磁场时,我们恢复了双层石墨烯的四倍朗道能级简并度。在零磁场和量子霍尔区之间的交叉处出现了意想不到的模式交叉。

英文摘要:

We report the fabrication of electrostatically defined nanostructures in encapsulated bilayer graphene, with leakage resistances below depletion gates as high as $R \sim 10~$G$Ω$. This exceeds previously reported values of $R =~$10 - 100 k$Ω$.\cite{Zou2010,Yan2010,Zhu2016a} We attribute this improvement to the use of a graphite back gate. We realize two split gate devices which define an electronic channel on the scale of the Fermi-wavelength. A channel gate covering the gap between the split gates varies the charge carrier density in the channel. We observe device-dependent conductance quantization of $ΔG = 2~e^2/h$ and $ΔG = 4~e^2/h$. In quantizing magnetic fields normal to the sample plane, we recover the four- fold Landau level degeneracy of bilayer graphene. Unexpected mode crossings appear at the crossover between zero magnetic field and the quantum Hall regime.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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