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arXiv · 2605.23363

Field evolution of the magnetic structure and spin Hamiltonian in Cs$_2$RuO$_4$

S. D. Nabi·E. Ressouche·D. G. Mazzone·J. Lass·R. Sibille·Z. Yan·S. Gvasaliya·A. Zheludev
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Abstract

We report neutron diffraction under applied magnetic fields and complementary zero-field neutron spectroscopy measurements on Cs$_2$RuO$_4$. Previous work [S. D. Nabi et al., Phys. Rev. B 112, 134436 (2025)] identified a spin-flop-like transition accompanied by a quantum critical point within the ordered phase, attributed to strong frustration between alternating single-ion anisotropy planes. Here, we quantitatively confirm the predicted field evolution of the magnetic structure using neutron diffraction. Furthermore, analysis of the excitation spectrum within an SU(3) spin-wave framework resolves previously undetermined parameters of the minimal spin Hamiltonian and lifts the associated degeneracies.

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S. D. Nabi, E. Ressouche, D. G. Mazzone, J. Lass, R. Sibille, Z. Yan, S. Gvasaliya, A. Zheludev. 2026-05-22. Field evolution of the magnetic structure and spin Hamiltonian in Cs$_2$RuO$_4$. https://doi.org/10.1103/n8rr-rgfv

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