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arXiv · 2404.01600

C-type antiferromagnetic structure of topological semimetal CaMnSb$_2$

Bo Li·Xu-Tao Zeng·Qianhui Xu·Fan Yang·Junsen Xiang·Hengyang Zhong·Sihao Deng·Lunhua He·Juping Xu·Wen Yin·Xingye Lu·Huiying Liu·Xian-Lei Sheng·Wentao Jin
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Abstract

Determination of the magnetic structure and confirmation of the presence or absence of inversion ($\mathcal{P}$) and time reversal ($\mathcal{T}$) symmetry is imperative for correctly understanding the topological magnetic materials. Here high-quality single crystals of the layered manganese pnictide CaMnSb$_2$ are synthesized using the self-flux method. De Haas-van Alphen oscillations indicate a nontrivial Berry phase of $\sim$ $\pi$ and a notably small cyclotron effective mass, supporting the Dirac semimetal nature of CaMnSb$_2$. Neutron diffraction measurements identify a C-type antiferromagnetic (AFM) structure below $T\rm_{N}$ = 303(1) K with the Mn moments aligned along the $a$ axis, which is well supported by the density functional theory (DFT) calculations. The corresponding magnetic space group is $Pn'm'a'$, preserving a $\mathcal{P}\times\mathcal{T}$ symmetry. Adopting the experimentally determined magnetic structure, band crossings near the Y point in momentum space and linear dispersions of the Sb $5p_{y,z}$ bands are revealed by the DFT calculations. Furthermore, our study predicts the possible existence of an intrinsic second-order nonlinear Hall effect in CaMnSb$_2$, offering a promising platform to study the impact of topological properties on nonlinear electrical transports in antiferromagnets.

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Bo Li, Xu-Tao Zeng, Qianhui Xu, Fan Yang, Junsen Xiang, Hengyang Zhong, Sihao Deng, Lunhua He, Juping Xu, Wen Yin, Xingye Lu, Huiying Liu, Xian-Lei Sheng, Wentao Jin. 2024-04-02. C-type antiferromagnetic structure of topological semimetal CaMnSb$_2$. https://doi.org/10.1088/0256-307x%2F41%2F3%2F037104

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