Moir\'e Kramers-Weyl Fermions from Structural Chirality with Ideal Radial Spin Texture

D. J. P. de Sousa; Seungjun Lee; Tony Low

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arXiv · 2409.06806

Moir\'e Kramers-Weyl Fermions from Structural Chirality with Ideal Radial Spin Texture

D. J. P. de Sousa·Seungjun Lee·Tony Low

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Abstract

We demonstrate that two-dimensional Kramers-Weyl fermions can be engineered in spin-orbit coupled twisted bilayers, where the chiral structure of these moir\'e systems breaks all mirror symmetries, confining Kramers-Weyl fermions to high-symmetry points in the Brillouin zone under time reversal symmetry. Our theoretical analysis reveals a symmetry-enforced Weyl-like interlayer moir\'e coupling that universally ensures an ideal radial spin-texture at arbitrary twist angles, under $C_{nz}$ symmetry with n>2. First principles density functional calculation confirm the realization of these fermions in twisted $\alpha$-In$_2$Se$_3$ bilayers, where flat bands and out-of-plane ferroelectric polarization in each layer guarantee two-dimensional Kramers-Weyl physics with perfectly ideal radial spin textures.

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D. J. P. de Sousa, Seungjun Lee, Tony Low. 2024-09-10. Moir\'e Kramers-Weyl Fermions from Structural Chirality with Ideal Radial Spin Texture. https://arxiv.org/abs/2409.06806

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