Moiré WSe2 中的双量子自旋霍尔相。

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

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引用次数: 0

摘要

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。

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Double Quantum Spin Hall Phase in Moiré WSe₂.

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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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

期刊介绍： Nano Letters serves as a dynamic platform for promptly disseminating original results in fundamental, applied, and emerging research across all facets of nanoscience and nanotechnology. A pivotal criterion for inclusion within Nano Letters is the convergence of at least two different areas or disciplines, ensuring a rich interdisciplinary scope. The journal is dedicated to fostering exploration in diverse areas, including: - Experimental and theoretical findings on physical, chemical, and biological phenomena at the nanoscale - Synthesis, characterization, and processing of organic, inorganic, polymer, and hybrid nanomaterials through physical, chemical, and biological methodologies - Modeling and simulation of synthetic, assembly, and interaction processes - Realization of integrated nanostructures and nano-engineered devices exhibiting advanced performance - Applications of nanoscale materials in living and environmental systems Nano Letters is committed to advancing and showcasing groundbreaking research that intersects various domains, fostering innovation and collaboration in the ever-evolving field of nanoscience and nanotechnology.