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arXiv 1304.5035cond-mat.mes-hall
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带隙石墨烯异质结中的量子霍尔效应

Quantum Hall effect in gapped graphene heterojunctions

J. L. Lado, J. W. González, J. Fernández-Rossier

摘要:

我们模拟了异质结构中的量子霍尔效应,该异质结构由两个具有不同间隙的石墨烯条带$Δ_1$和$Δ_2$制成。我们考虑两种主要情况,$Δ_1=0,Δ_2\neq0$和$Δ_1=-Δ_2$。它们在一个基本方面是不同的:只有后者的功能扭结状态,当谷间耦合是不存在的,受到保护,免受背散射。我们计算的两个终端电导的异质结构的沟道长度高达430 nm,在两个运输配置,平行和垂直的界面。通过研究无序对沿边界输运的影响,我们量化了扭结态对背散射的鲁棒性。垂直于边界的输运显示了界面态如何为导电边缘态打开反向散射通道,破坏了均匀间隙的石墨烯霍尔棒所具有的完美电导量子化。我们的研究结果可以是相关的石墨烯沉积在六方氮化硼的研究,以及模型石墨烯的相互作用驱动的间隙相与两个等效相分离的域壁。

英文摘要:

We model the quantum Hall effect in heterostructures made of two gapped graphene stripes with different gaps, $Δ_1$ and $Δ_2$. We consider two main situations, $Δ_1=0,Δ_2\neq0$ and $Δ_1=-Δ_2$. They are different in a fundamental aspect: only the latter feature kink states that, when intervalley coupling is absent, are protected against backscattering. We compute the two terminal conductance of heterostructures with channel length up to 430 nm, in two transport configurations, parallel and perpendicular to the interface. By studying the effect of disorder on the transport along the boundary, we quantify the robustness of kink states with respect to backscattering. Transport perpendicular to the boundary shows how interface states open a backscattering channel for the conducting edge states, spoiling the perfect conductance quantization featured by the homogeneously gapped graphene Hall bars. Our results can be relevant for the study of graphene deposited on hexagonal Boron-Nitride as well as to model graphene with an interaction-driven gapped phase with two equivalent phases separated by a domain wall.

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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