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arXiv · 2303.02587

Coupling of magnetism and Dirac fermions in YbMnSb2

Xiao Hu·Aashish Sapkota·Zhixiang Hu·Andrei T. Savici·Alexander I. Kolesnikov·John M. Tranquada·Cedomir Petrovic·Igor A. Zaliznyak
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Abstract

We report inelastic neutron scattering measurements of magnetic excitations in YbMnSb2, a low-carrier-density Dirac semimetal in which the antiferromagnetic Mn layers are interleaved with Sb layers that host Dirac fermions. We observe a considerable broadening of spin waves, which is consistent with substantial spin fermion coupling. The spin wave damping, $\gamma$, in YbMnSb2 is roughly twice larger compared to that in a sister material, YbMnBi2, where an indication of a small damping consistent with theoretical analysis of the spin-fermion coupling was reported. The inter-plane interaction between the Mn layers in YbMnSb2 is also much stronger, suggesting that the interaction mechanism is rooted in the same spin-fermion coupling. Our results establish the systematics of spin-fermion interactions in layered magnetic Dirac materials.

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Xiao Hu, Aashish Sapkota, Zhixiang Hu, Andrei T. Savici, Alexander I. Kolesnikov, John M. Tranquada, Cedomir Petrovic, Igor A. Zaliznyak. 2023-03-05. Coupling of magnetism and Dirac fermions in YbMnSb2. https://doi.org/10.1103/physrevb.107.l201117

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