Nearly-Resonant Crystalline-Phononic Coupling in Quantum Spin Liquid Candidate CsYbSe${}_2$

Abstract

CsYbSe${}_2$, a recently identified quantum spin liquid (QSL) candidate, exhibits strong crystal electric field (CEF) excitations. Here, we identify phonon and CEF modes with Raman spectroscopy and observe strong CEF-phonon mixing resulting in a vibronic bound state. Complex, mesoscale interplay between phonon modes and CEF modes is observed in real space, and an unexpected nearly resonant condition is satisfied, yielding up to fifth-order combination modes, with a total of 17 modes identified in the spectra. This study paves the way to coherent control of possible QSL ground states with optically accessible CEF-phonon manifolds and mesoscale engineering of CEF-phonon interactions.

16 pages, 10 figures; Comments: fixed bbl

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Cited by in corpus (5)

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• Rare-Earth Chalcogenides: An Inspiring Playground For Exploring Frustrated Magnetism
• Crystal-field effects competing with spin-orbit interactions in NaCeO${}_2$
• Yb${}^{3+}$ $f$-$f$ excitations in NaYbSe${}_2$: benchmarking embedded-cluster quantum chemical schemes for 4$f$ insulators
• More bridging ligands activate direct exchange: the case of anisotropic Kitaev effective magnetic interactions