Dielectric relaxation in the quantum multiferroics Rb$_2$Cu$_2$Mo$_3$O$_{12}$ and Cs$_2$Cu$_2$Mo$_3$O$_{12}$

D. Flavián; P. A. Volkov; S. Hayashida; K. Yu. Povarov; S. Gvasaliya; P. Chandra; A. Zheludev

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arXiv · 2406.12690

Dielectric relaxation in the quantum multiferroics Rb$_2$Cu$_2$Mo$_3$O$_{12}$ and Cs$_2$Cu$_2$Mo$_3$O$_{12}$

D. Flavián·P. A. Volkov·S. Hayashida·K. Yu. Povarov·S. Gvasaliya·P. Chandra·A. Zheludev

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Abstract

Motivated by the recent discovery of dielectric relaxation by quantum critical magnons in Cs$_2$Cu$_2$Mo$_3$O$_{12}$, we conduct a detailed analysis of its dielectric response and compare it to that in the isostructural compound Rb$_2$Cu$_2$Mo$_3$O$_{12}$. Measurements in the vicinity of the field-induced magnon softening show that its description in terms of 3D Bose-Einstein condensation of magnons quantum critical point is unaltered by the presence of dielectric relaxation. We also demonstrate the existence of dielectric relaxation anomalies at 19 K in Rb$_2$Cu$_2$Mo$_3$O$_{12}$ and discuss the implications for the microscopic origin of dielectric activity in two compounds.

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D. Flavián, P. A. Volkov, S. Hayashida, K. Yu. Povarov, S. Gvasaliya, P. Chandra, A. Zheludev. 2024-06-18. Dielectric relaxation in the quantum multiferroics Rb$_2$Cu$_2$Mo$_3$O$_{12}$ and Cs$_2$Cu$_2$Mo$_3$O$_{12}$. https://arxiv.org/abs/2406.12690

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