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arXiv · 1908.04872

Magnetic structure and excitations of the topological semimetal YbMnBi$_2$

Jian-Rui Soh·Henrik Jacobsen·Bachir Ouladdiaf·Alexandre Ivanov·Andrea Piovano·Tim Tejsner·Zili Feng·Hongyuan Wang·Hao Su·Yanfeng Guo·Youguo Shi·Andrew T. Boothroyd
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Abstract

We investigated the magnetic structure and dynamics of YbMnBi$_2$, with elastic and inelastic neutron scattering, to shed light on the topological nature of the charge carriers in the antiferromagnetic phase. We confirm C-type antiferromagnetic ordering of the Mn spins below $T_{\rm N} = 290$ K, and determine that the spins point along the $c$-axis to within about $3^\circ$. The observed magnon spectrum can be described very well by the same effective spin Hamiltonian as was used previously to model the magnon spectrum of CaMnBi$_2$. Our results show conclusively that the creation of Weyl nodes in YbMnBi$_2$ by the time-reversal-symmetry breaking mechanism can be excluded in the bulk.

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Jian-Rui Soh, Henrik Jacobsen, Bachir Ouladdiaf, Alexandre Ivanov, Andrea Piovano, Tim Tejsner, Zili Feng, Hongyuan Wang, Hao Su, Yanfeng Guo, Youguo Shi, Andrew T. Boothroyd. 2019-08-13. Magnetic structure and excitations of the topological semimetal YbMnBi$_2$. https://doi.org/10.1103/physrevb.100.144431

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