One-Dimensional Edge Transport in Few-Layer WTe2

Artem Kononov; Artem Kononov; Gulibusitan Abulizi; Kejian Qu; Jiaqiang Yan; Jiaqiang Yan; David Mandrus; David Mandrus; Kenji Watanabe; Takashi Taniguchi; Christian Schönenberger; Christian Schönenberger

doi:10.1021/acs.nanolett.0c00658

One-Dimensional Edge Transport in Few-Layer WTe₂

Artem Kononov, Artem Kononov, Gulibusitan Abulizi, Kejian Qu, Jiaqiang Yan, Jiaqiang Yan, David Mandrus, David Mandrus, Kenji Watanabe, Takashi Taniguchi, Christian Schönenberger, Christian Schönenberger

Correlated Electron Materials

Research output: Contribution to journal › Article › peer-review

60 Scopus citations

Abstract

WTe2 is a layered transitional-metal dichalcogenide (TMD) with a number of intriguing topological properties. Recently, WTe2 has been predicted to be a higher-order topological insulator (HOTI) with topologically protected hinge states along the edges. The gapless nature of WTe2 complicates the observation of one-dimensional (1D) topological states in transport due to their small contribution relative to the bulk. Here, we study the behavior of the Josephson effect in magnetic field to distinguish edge from bulk transport. The Josephson effect in few-layer WTe2 reveals 1D states residing on the edges and steps. Moreover, our data demonstrates a combination of Josephson transport properties observed solely in another HOTI - bismuth, including Josephson transport over micrometer distances, extreme robustness in a magnetic field, and nonsinusoidal current-phase relation (CPR). Our observations strongly suggest the topological origin of the 1D states and that few-layer WTe2 is a HOTI.

Original language	English
Pages (from-to)	4228-4233
Number of pages	6
Journal	Nano Letters
Volume	20
Issue number	6
DOIs	https://doi.org/10.1021/acs.nanolett.0c00658
State	Published - Jun 10 2020

Funding

We thank D. Indolese for the help with measurements of the critical current and fruitful discussions, M. Endres for his help with the exfoliation and identification of WTe flakes, M. Joodaki for her contribution to the optical identification of WTe flakes thickness, and A. Baumgartner for fruitful discussions. A.K. was supported by the Georg H. Endress foundation. This project has received further funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement no. 787414 TopSupra), from the Swiss National Science Foundation through the National Centre of Competence in Research Quantum Science and Technology (QSIT), and from the Swiss Nanoscience Institute (SNI). K.W. and T.T. acknowledge support from the Elemental Strategy Initiative conducted by MEXT, Japan, and CREST (JPMJCR15F3), JST. D.M. and J.Y. acknowledge support from the U.S. Department of Energy (U.S. DOE), Office of Science, Basic Energy Sciences (BES), Materials Sciences and Engineering Division. 2 2

Keywords

1D edge states
Josephson effect
WTe
higher order topological insulators
nonsinusoidal CPR

Access to Document

10.1021/acs.nanolett.0c00658

Cite this

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title = "One-Dimensional Edge Transport in Few-Layer WTe2",

abstract = "WTe2 is a layered transitional-metal dichalcogenide (TMD) with a number of intriguing topological properties. Recently, WTe2 has been predicted to be a higher-order topological insulator (HOTI) with topologically protected hinge states along the edges. The gapless nature of WTe2 complicates the observation of one-dimensional (1D) topological states in transport due to their small contribution relative to the bulk. Here, we study the behavior of the Josephson effect in magnetic field to distinguish edge from bulk transport. The Josephson effect in few-layer WTe2 reveals 1D states residing on the edges and steps. Moreover, our data demonstrates a combination of Josephson transport properties observed solely in another HOTI - bismuth, including Josephson transport over micrometer distances, extreme robustness in a magnetic field, and nonsinusoidal current-phase relation (CPR). Our observations strongly suggest the topological origin of the 1D states and that few-layer WTe2 is a HOTI.",

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AU - Abulizi, Gulibusitan

AU - Qu, Kejian

AU - Yan, Jiaqiang

AU - Mandrus, David

AU - Watanabe, Kenji

AU - Taniguchi, Takashi

AU - Schönenberger, Christian

PY - 2020/6/10

Y1 - 2020/6/10

N2 - WTe2 is a layered transitional-metal dichalcogenide (TMD) with a number of intriguing topological properties. Recently, WTe2 has been predicted to be a higher-order topological insulator (HOTI) with topologically protected hinge states along the edges. The gapless nature of WTe2 complicates the observation of one-dimensional (1D) topological states in transport due to their small contribution relative to the bulk. Here, we study the behavior of the Josephson effect in magnetic field to distinguish edge from bulk transport. The Josephson effect in few-layer WTe2 reveals 1D states residing on the edges and steps. Moreover, our data demonstrates a combination of Josephson transport properties observed solely in another HOTI - bismuth, including Josephson transport over micrometer distances, extreme robustness in a magnetic field, and nonsinusoidal current-phase relation (CPR). Our observations strongly suggest the topological origin of the 1D states and that few-layer WTe2 is a HOTI.

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