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arXiv · 2101.05143

Direct Observation of Collective Electronuclear Modes About a Quantum Critical Point

M. Libersky·R. D. McKenzie·D. M. Silevitch·P. C. E. Stamp·T. F. Rosenbaum
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Abstract

We directly measure the low energy excitation modes of the quantum Ising magnet LiHoF$_4$ using microwave spectroscopy. Instead of a single electronic mode, we find a set of collective electronuclear modes, in which the spin-$1/2$ Ising electronic spins hybridize with the bath of spin-$7/2$ Ho nuclear spins. The lowest-lying electronuclear mode softens at the approach to the quantum critical point, even in the presence of disorder. This softening is rapidly quenched by a longitudinal magnetic field. Similar electronuclear structures should exist in other spin-based quantum Ising systems.

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M. Libersky, R. D. McKenzie, D. M. Silevitch, P. C. E. Stamp, T. F. Rosenbaum. 2021-10-13. Direct Observation of Collective Electronuclear Modes About a Quantum Critical Point. https://doi.org/10.1103/physrevlett.127.207202

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