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arXiv · 2111.03919

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

Yun-Yi Pai·Claire E. Marvinney·Liangbo Liang·Jie Xing·Allen Scheie·Alexander A. Puretzky·Gábor B. Halász·Xun Li·Rinkle Juneja·Athena S. Sefat·David Parker·Lucas Lindsay·Benjamin J. Lawrie
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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.

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Yun-Yi Pai, Claire E. Marvinney, Liangbo Liang, Jie Xing, Allen Scheie, Alexander A. Puretzky, Gábor B. Halász, Xun Li, Rinkle Juneja, Athena S. Sefat, David Parker, Lucas Lindsay, Benjamin J. Lawrie. 2021-11-06. Nearly-Resonant Crystalline-Phononic Coupling in Quantum Spin Liquid Candidate CsYbSe$_2$. https://doi.org/10.1039/d1tc05934c

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