Unveiling Hidden Magnons with Anomalous Rotational Symmetry

Fuente: arXiv
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Main Authors: Wulferding, Dirk, Gabriele, Francesco, Brzezicki, Wojciech, Cuoco, Mario, Kim, Changyoung, Lettieri, Mariateresa, Guarino, Anita, Vecchione, Antonio, Fittipaldi, Rosalba, Forte, Filomena
Format: Preprint
Published: 2026
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author Wulferding, Dirk
Gabriele, Francesco
Brzezicki, Wojciech
Cuoco, Mario
Kim, Changyoung
Lettieri, Mariateresa
Guarino, Anita
Vecchione, Antonio
Fittipaldi, Rosalba
Forte, Filomena
author_facet Wulferding, Dirk
Gabriele, Francesco
Brzezicki, Wojciech
Cuoco, Mario
Kim, Changyoung
Lettieri, Mariateresa
Guarino, Anita
Vecchione, Antonio
Fittipaldi, Rosalba
Forte, Filomena
contents Correlated materials with competing spin-orbit and crystal-field interactions can host composite spin-orbital magnons that are highly susceptible to structural and electronic perturbations, enabling the control of magnetic dynamics beyond spin-only physics. Using Raman spectroscopy on Ca$_2$RuO$_4$, we show that the partial substitution of Ru with Mn reconstructs the magnon spectrum and reveals one-magnon modes that are hidden in the undoped state. We demonstrate that the transition-metal substitution activates otherwise symmetry-forbidden magnon modes through mirror-symmetry breaking of the underlying spin-orbital configuration. This effect can be theoretically explained by the local structural distortions induced in the RuO$_6$ octahedra near the dopant, that enable the observation of mixed-parity one-magnon modes. These excitations display a distinctive polarization dependence, with a lowering from fourfold to twofold rotational symmetry arising from the mixed-parity character of the coupled magnons and interference between resonant and nonresonant scattering channels. Our results show that spin-orbit-lattice entanglement provides a route to tailoring collective magnetic excitations and their polarization response in spin-orbit-coupled correlated systems.
format Preprint
id arxiv_https___arxiv_org_abs_2601_13219
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Unveiling Hidden Magnons with Anomalous Rotational Symmetry
Wulferding, Dirk
Gabriele, Francesco
Brzezicki, Wojciech
Cuoco, Mario
Kim, Changyoung
Lettieri, Mariateresa
Guarino, Anita
Vecchione, Antonio
Fittipaldi, Rosalba
Forte, Filomena
Strongly Correlated Electrons
Correlated materials with competing spin-orbit and crystal-field interactions can host composite spin-orbital magnons that are highly susceptible to structural and electronic perturbations, enabling the control of magnetic dynamics beyond spin-only physics. Using Raman spectroscopy on Ca$_2$RuO$_4$, we show that the partial substitution of Ru with Mn reconstructs the magnon spectrum and reveals one-magnon modes that are hidden in the undoped state. We demonstrate that the transition-metal substitution activates otherwise symmetry-forbidden magnon modes through mirror-symmetry breaking of the underlying spin-orbital configuration. This effect can be theoretically explained by the local structural distortions induced in the RuO$_6$ octahedra near the dopant, that enable the observation of mixed-parity one-magnon modes. These excitations display a distinctive polarization dependence, with a lowering from fourfold to twofold rotational symmetry arising from the mixed-parity character of the coupled magnons and interference between resonant and nonresonant scattering channels. Our results show that spin-orbit-lattice entanglement provides a route to tailoring collective magnetic excitations and their polarization response in spin-orbit-coupled correlated systems.
title Unveiling Hidden Magnons with Anomalous Rotational Symmetry
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2601.13219