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arXiv · 2603.05734

Magnetoelastic signatures of the conical state and charge density waves in antiferromagnetic FeGe

L. Prodan·J. Sourd·S. Zherlitsyn·L. Chioncel
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Abstract

Kagome systems host intertwined spin, charge, and lattice degrees of freedom that drive emergent collective states. Here, we identify two distinct energy scales in the noncollinear kagome magnet FeGe: a field-tunable magnetic fluctuation channel at $\sim 35$~K associated with the conical state, and a field-independent channel at $\sim 100$~K linked to charge-density-wave fluctuations. Ultrasound measurements provide direct access to the exchange-renormalized magnetic stiffness, whose softening governs the acoustic anomaly and follows a symmetry-constrained quadratic field dependence. We further predict a linear temperature dependence of neutron diffraction intensities at fixed field and a quadratic field suppression at fixed temperature. These results identify magnetic stiffness as a key control parameter of spin-lattice dynamics and establish ultrasound as a sensitive probe of coupled collective modes.

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L. Prodan, J. Sourd, S. Zherlitsyn, L. Chioncel. 2026-03-05. Magnetoelastic signatures of the conical state and charge density waves in antiferromagnetic FeGe. https://arxiv.org/abs/2603.05734

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