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Van der Waals heterostructures offer great versatility to tailor unique interactions at the atomically flat interfaces between dissimilar layered materials and induce novel physical phenomena. By bringing monolayer 1T’ WTe2, a two-dimensional quantum spin Hall insulator, and few-layer Cr2Ge2Te6, an insulating ferromagnet, into close proximity in an heterostructure, we introduce an interfacial exchange interaction to transform the former into a ferromagnetic quantum spin Hall insulator, manifested by the anomalous Nernst effect, anomalous Hall effect as well as anisotropic magnetoresistance effect. Using local electrodes, we identify separate transport contributions from the metallic edge and insulating bulk components. When driven by an AC current excitation, the second harmonic voltage responses closely resemble the anomalous Nernst responses to an AC temperature gradient generated by a nonlocal heater, which appear as nonreciprocal signals with respect to the magnetization orientation. Our results shed light on the nature of the ferromagnetic quantum spin Hall insulator edge states that are qualitatively distinct from the chiral or helical edge states in other topological systems.

Rights:

• Creative Commons BY Attribution 4.0 International
  

Keyword: Van der Waals heterostructures, ferromagnetism, quantum spin Hall

Date published: 2022-09-01

Publisher: Springer Science and Business Media LLC

Journal:

• Nature Communications (ISSN: 20411723) vol. 13 issue. 1 5134

Funding:

• U.S. Department of Energy DE-FG02-07ER46351
• National Science Foundation NSF-ECCS-2051450

Manuscript type: Publisher's version (Version of record)

MDR DOI:

First published URL: https://doi.org/10.1038/s41467-022-32808-w

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Updated at: 2025-02-27 12:30:19 +0900

Published on MDR: 2025-02-27 12:30:19 +0900