Hidden non-collinear spin-order induced topological surface states

Zengle Huang; Hemian Yi; Daniel Kaplan; Lujin Min; Hengxin Tan; Ying-ting Chan; Zhiqiang Mao; Binghai Yan; Cui-Zu Chang; Weida Wu

arXiv · 2309.06632

Hidden non-collinear spin-order induced topological surface states

Zengle Huang·Hemian Yi·Daniel Kaplan·Lujin Min·Hengxin Tan·Ying-ting Chan·Zhiqiang Mao·Binghai Yan·Cui-Zu Chang·Weida Wu

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Abstract

Rare-earth monopnictides are a family of materials simultaneously displaying complex magnetism, strong electronic correlation, and topological band structure. The recently discovered emergent arc-like surface states in these materials have been attributed to the multi-wave-vector antiferromagnetic order, yet the direct experimental evidence has been elusive. Here we report the observation of non-collinear antiferromagnetic order with multiple modulations using spin-polarized scanning tunneling microscopy. Moreover, we discover a hidden spin-rotation transition of single-to-multiple modulations 2 K below the Neel temperature. The hidden transition coincides with the onset of the surface states splitting observed by our angle-resolved photoemission spectroscopy measurements. Single modulation gives rise to a band inversion with induced topological surface states in a local momentum region while the full Brillouin zone carries trivial topological indices, and multiple modulation further splits the surface bands via non-collinear spin tilting, as revealed by our calculations. The direct evidence of the non-collinear spin order in NdSb not only clarifies the mechanism of the emergent topological surface states, but also opens up a new paradigm of control and manipulation of band topology with magnetism.

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Zengle Huang, Hemian Yi, Daniel Kaplan, Lujin Min, Hengxin Tan, Ying-ting Chan, Zhiqiang Mao, Binghai Yan, Cui-Zu Chang, Weida Wu. 2023-09-12. Hidden non-collinear spin-order induced topological surface states. https://arxiv.org/abs/2309.06632

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