Cavity-magnon-polariton spectroscopy of strongly hybridized electro-nuclear spin excitations in LiHoF4

• Published in: Scientific reports Vol. 14; no. 1; pp. 25227 - 14
• Main Authors: Yang, Yikai, Babkevich, Peter, Gaal, Richard, Živković, Ivica, Rønnow, Henrik M.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 24-10-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 639/624/400/482; 639/766/119/2795; 639/766/119/997; Electrons; Humanities and Social Sciences; Magnetic fields; multidisciplinary; Neutrons; NMR; Nuclear magnetic resonance; Phase transitions; Science; Science (multidisciplinary); Spectroscopy; Spectrum analysis
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-024-75978-x

We first present a formalism that incorporates the input-output formalism and the linear response theory to employ cavity-magnon-polariton coupling as a spectroscopic tool for investigating strongly hybridized electro-nuclear spin excitations. A microscopic relation between the generalized susceptibility and the scattering parameter
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S
11
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in strongly hybridized cavity-magnon-polariton systems has been derived without resorting to semi-classical approximations. The formalism is then applied to both analyze and simulate a specific systems comprising a model quantum Ising magnet (
LiHoF
4
) and a high-finesse 3D re-entrant cavity resonator. Quantitative information on the electro-nuclear spin states in
LiHoF
4
is extracted, and the experimental observations across a broad parameter range were numerically reproduced, including an external magnetic field traversing a quantum critical point. The method potentially opens a new avenue not only for further studies on the quantum phase transition in
LiHoF
4
but also for a wide range of complex magnetic systems.