Double Quantum Spin Hall Phase in Moiré WSe₂.

IF 9.6 1区材料科学 Q1 CHEMISTRY, MULTIDISCIPLINARY

Nano Letters Pub Date : 2024-11-06 DOI:10.1021/acs.nanolett.4c05308

Kaifei Kang, Yichen Qiu, Kenji Watanabe, Takashi Taniguchi, Jie Shan, Kin Fai Mak

引用次数: 0

Abstract

Quantum spin Hall (QSH) insulators are topologically protected phases of matter in two dimensions that can support a pair of helical edge states surrounding an insulating bulk. A higher (even) number of helical edge state pairs is usually not possible in real materials because spin mixing would gap out the edge states. Here, we report experimental evidence for a QSH phase with one and two pairs of helical edge states in twisted bilayer WSe₂ at Moiré hole filling factor ν = 2 and 4, respectively. We observe nearly quantized (within 10%) resistance plateaus of $\frac{h}{ν e^{2}}$ and large nonlocal transport at ν = 2 and 4 while the bulk is insulating. The resistance is independent of the out-of-plane magnetic field and increases under an in-plane magnetic field. The results agree with quantum transport of helical edge states in a material with high spin Chern bands protected by Ising spin conservation symmetry.

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Moiré WSe2 中的双量子自旋霍尔相。

量子自旋霍尔（QSH）绝缘体是二维物质的拓扑保护相，可支持一对螺旋边缘态包围一个绝缘体。在实际材料中，通常不可能存在数量更多（偶数）的螺旋边缘态对，因为自旋混合会使边缘态出现间隙。在这里，我们报告了实验证据，证明扭曲双层 WSe2 在莫伊里空穴填充因子 ν = 2 和 4 条件下分别具有一对和两对螺旋边缘态的 QSH 相。我们观察到在 ν = 2 和 4 时，hνe2 的电阻几乎达到量子化（10% 以内），并且存在大量非局部输运，而主体是绝缘的。电阻与平面外磁场无关，但在平面内磁场作用下会增大。结果与具有高自旋切尔带并受伊辛自旋守恒对称性保护的材料中螺旋边缘态的量子输运一致。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nano Letters 工程技术-材料科学：综合

CiteScore

16.80

自引率

2.80%

发文量

1182

审稿时长

1.4 months

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Double Quantum Spin Hall Phase in Moiré WSe2.

Abstract

Double Quantum Spin Hall Phase in Moiré WSe₂.