Evidence of the fractional quantum spin Hall effect in moiré MoTe2

Kang, Kaifei; Shen, Bowen; Qiu, Yichen; Zeng, Yihang; Xia, Zhengchao; Watanabe, Kenji; Taniguchi, Takashi; Shan, Jie; Mak, Kin Fai

doi:10.1038/s41586-024-07214-5

Cited by 37 publications

(3 citation statements)

References 52 publications

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“…In particular, our calculations reveal multiple flat bands with Chern numbers all equal to +1 at around 2°, indicating the possibility of mimicking higher Landau-level physics in the absence of magnetic field. The presence of multiple bands of Chern number +1 has been confirmed by a recent experimental measurement 46 .…”

Section: Resultssupporting

confidence: 53%

Polarization-driven band topology evolution in twisted MoTe2 and WSe2

Zhang,

Wang,

Liu

et al. 2024

Nat Commun

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Motivated by recent experimental observations of opposite Chern numbers in R-type twisted MoTe2 and WSe2 homobilayers, we perform large-scale density-functional-theory calculations with machine learning force fields to investigate moiré band topology across a range of twist angles in both materials. We find that the Chern numbers of the moiré frontier bands change sign as a function of twist angle, and this change is driven by the competition between moiré ferroelectricity and piezoelectricity. Our large-scale calculations, enabled by machine learning methods, reveal crucial insights into interactions across different scales in twisted bilayer systems. The interplay between atomic-level relaxation effects and moiré-scale electrostatic potential variation opens new avenues for the design of intertwined topological and correlated states, including the possibility of mimicking higher Landau level physics in the absence of magnetic field.

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Section: Resultssupporting

confidence: 53%

Polarization-driven band topology evolution in twisted MoTe2 and WSe2

Zhang,

Wang,

Liu

et al. 2024

Nat Commun

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“…Realizing quantum spin Hall insulators that host robust helical edge states that can be manipulated in devices is of great interest for novel spintronic and quantum applications. − Candidates for quantum spin Hall insulators include atomically thin layers − and quantum well structures of two-dimensional topological insulators (2D TIs). − While idealized models of 2D TI heterostructures are well established, there are many parameters in practical heterostructures that can result in substantially modified electronic states. One of the most important is structural inversion asymmetry (SIA), which is caused by inequivalent top and bottom interfaces. − Strong SIA causes a Rashba-like splitting of the spin-degenerate, massive Dirac bands of the 2D TI, which can destroy the band inversion at k = 0 and thus the 2D TI (see Figure a).…”

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confidence: 99%

mentioning

confidence: 99%

Tuning Displacement Fields in a Two-Dimensional Topological Insulator Using Nanopatterned Gates

Rashidi,

Ahadi,

Munyan

et al. 2024

Nano Lett.

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Epitaxial heterostructures with topological insulators enable novel quantum phases and practical device applications. Their topological electronic states are sensitive to the microscopic parameters, including structural inversion asymmetry (SIA), which is an inherent feature of many real heterostructures. Controlling SIA is challenging, because it requires the ability to tune the displacement field across the topological film. Here, using nanopatterned gates, we demonstrate a tunable displacement field in a heterostructure of the twodimensional topological insulator cadmium arsenide. Transport studies in magnetic fields reveal an extreme sensitivity of the band inversion to SIA. We show that a relatively small displacement field (∼50 mV/nm) converts the crossing of the two zeroth Landau levels in magnetic field to an avoided crossing, signaling a change to trivial band order. This work demonstrates a universal methodology for tuning electronic states in topological thin films.

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Effect of lattice relaxation on electronic spectra of helically twisted trilayer graphene: large-scale atomistic simulation approach

Jang

2024

J. Korean Phys. Soc.

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Evidence of the fractional quantum spin Hall effect in moiré MoTe2

Cited by 37 publications

References 52 publications

Polarization-driven band topology evolution in twisted MoTe2 and WSe2

Polarization-driven band topology evolution in twisted MoTe2 and WSe2

Tuning Displacement Fields in a Two-Dimensional Topological Insulator Using Nanopatterned Gates

Effect of lattice relaxation on electronic spectra of helically twisted trilayer graphene: large-scale atomistic simulation approach

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