Determination of the spin orientation of helical electrons in monolayer WTe2

Abstract

Monolayer WTe2 is predicted to be a quantum spin Hall insulator (QSHI) and electron transport along its edges has been experimentally observed. However, the 'smoking gun' of QSHI, spin momentum locking of the edge electrons, has not been experimentally demonstrated. We propose a model to establish the relationship between the anisotropic magnetoresistance (AMR) and spin orientation of the helical electrons in WTe2. Based on the predictions of the model, angular dependent magnetoresistance measurements were carried out. The experimental results fully supported the model and the spin orientation of the helical edge electrons was determined. Our results not only demonstrate that WTe2 is indeed a QSHI, but also suggest a convenient method to determine the spin orientation of other QSHIs.

32 pages, 11 figures

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Cited by in corpus (5)

• A gate-tunable quantum phase transition in a topological excitonic insulator
• Quantum spin Hall effect protected by spin U(1) quasisymmetry
• Edge spin transport in the disordered two-dimensional topological insulator WTe${}_2$
• Inverse Ising effect and Ising magnetoresistance
• Persistent spin texture preserved by local symmetry in graphene/WTe${}_2$ heterostructure