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Magneto-Elastic Interaction in Y$_3$Cu$_9$(OH)$_{19}$Cl$_{8}$

6O-02
Jul 8, 2025, 2:45 PM
15m
ORAL Topic 6 - Low-dimensional magnetic materials, molecular magnets and ferrofluids Section S6

Speaker

Petr Doležal (Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University)

Description

Quantum Spin Liquid (QSL) is a ground state of condensed matter, which is characterized by the absence of magnetic order down to the lowest temperatures along with long-range entanglement of fluctuating spin excitations [1]. Such a state of matter can be promoted by magnetic frustration which prevents the magnetic moments from antiferromagnetic ordering. There are many lattices created by magnetic ions exhibiting magnetic frustration. One of them is the two-dimensional kagome lattice with a high degree of frustration consisting of corner-sharing equilateral triangles. Although the concept is simple, finding such compounds with paramagnetic ions on a regular kagome lattice is quite complicated. The mineral herbertsmithite was considered as a very promising compound, but here the kagome lattice contains impurity spins created by the partial mixing of Zn and Cu atoms within and between the kagome planes. As a consequence, the magnetic properties at low temperatures are dominated by these impurities. Here we present the study of a related compound to herbertsmithite having a slightly distorted kagome lattice, but without impurity spins.

Y-kapellasite is yttrium copper hydroxychloride with the chemical formula Y$_3$Cu$_9$(OH)$_{19}$Cl$_8$, crystallizing in the rhombohedral crystal structure $R-3$ (148) [2]. The compound is antiferromagnetic below $T_N = 2.2$ K [2]. An anomalous behavior was found in the temperature dependence of thermal expansion around $32$ K, measured by dilatometry [3]. This finding rises the question whether there is any structural transition, but the X-ray and neutron diffraction experiments were inconclusive. We present the study of lattice dynamics studied by infrared spectroscopy. The obtained results are compared with the ab initio calculations and suggest the lowering of crystal lattice symmetry. The main crystal modification is probably caused by H atoms. We also observed the softening of low-energy phonons, which can be a sign of enhanced magnetoelastic interactions.

Acknowledgements

This work was supported by the Czech Science Foundation - project GAČR 23-06810O.

References

[1] L. Balents, “Spin liquids in frustrated magnets,” Nature, vol. 464, no. 7286. Springer Science and Business Media LLC, pp. 199–208, Mar. 10, 2010. https://doi.org/10.1038/nature08917
[2] P. Puphal et al., “Kagome quantum spin systems in the atacamite family,” Physical Review Materials, vol. 2, no. 6. American Physical Society (APS), Jun. 29, 2018. https://doi.org/10.1103/physrevmaterials.2.063402
[3] D. Chatterjee et al., "From spin liquid to magnetic ordering in the anisotropic kagome Y-kapellasite Y3Cu9(OH)19Cl8: A single-crystal study," Physical Review B, vol. 107, no. 12. American Physical Society (APS), Mar. 28, 2023. https://doi.org/10.1103/physrevb.107.125156

Primary author

Petr Doležal (Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University)

Co-authors

Tobias Biesner (Physikalisches Institut, Universität Stuttgart) Ying Li (Goethe University Frankfurt, Xi'an Jiaotong University) Roy Mathew (Physikalisches Institut, Universität Stuttgart) Seulki Roh (Physikalisches Institut, Universität Stuttgart) Roser Valenti (Institut für Theoretische Physik, Goethe-Universität Frankfurt) Martin Dressel (Physikalisches Institut, Universität Stuttgart) Pascal Puphal (Max Planck Institute for Solid State Research, Stuttgart) Andrej Pustogow (Technische Universitat Wien)

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