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arXiv 0806.2429cond-mat.mes-hall
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石墨烯中n=0 Laudau能级的边缘态

Edge states for the n=0 Laudau level in graphene

Mitsuhiro Arikawa, Yasuhiro Hatsugai, Hideo Aoki

摘要:

在反常量子霍尔效应(QHE)中,石墨烯的一个标志,磁场中的边缘状态的性质提出了一个重要的问题,因为边缘和体积在QHE中应该密切相关。在这里,我们已经从理论上研究了边缘状态,重点是E=0的边缘模式,这是不寻常的,因为该模式是嵌入在n=0的体朗道能级,而通常的QHE边缘模式驻留在相邻的朗道能级。在这里,我们表明,n=0的朗道能级,包括边缘模式,有一个波函数振幅沿锯齿形边缘积累,其宽度尺度与磁长度,l_B。这与通常的QHE形成对比,其中电荷从边缘耗尽。其影响是:(i)强磁场中的E=0边缘态在蜂窝晶格中有拓扑起源,因此它们在连续(“无质量狄拉克”)模型之外。(ii)边模贡献仅代数地衰减到体中,但这被体贡献“拓扑地”补偿,导致在l_B上的累积。(iii)这里得到的真实空间行为应该在STM实验中观察到。

英文摘要:

In the anomalous quantum Hall effect (QHE), a hallmark of graphene, nature of the edge states in magnetic fields poses an important question, since the edge and bulk should be intimately related in QHE. Here we have theoretically studied the edge states, focusing on the E=0 edge mode, which is unusual in that the mode is embedded right within the n=0 bulk Landau level, while usual QHE edge modes reside across adjacent Landau levels. Here we show that the n=0 Landau level, including the edge mode, has a wave function amplitude accumulated along zigzag edges whose width scales with the magnetic length, l_B. This contrasts with the usual QHE where the charge is depleted from the edge. The implications are: (i) The E=0 edge states in strong magnetic fields have a topological origin in the honeycomb lattice, so that they are outside the continuum ("massless Dirac") model. (ii) The edge-mode contribution decays only algebraically into the bulk, but this is "topologically" compensated by the bulk contribution, resulting in the accumulation over l_B. (iii) The real space behavior obtained here should be observable in STM experiments.

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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