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Free keywords:
Neutron scattering, Phonons, Quantum theory, Single crystals, Temperature, BEDT-TTF, Breathing modes, Low-temperature state, Neutron scattering measurements, Phonon damping, Quantum spin liquid, Renormalization effects, State based, Valence-bond solids, κ-(BEDT-TTF)2Cu2, Damping
Abstract:
The low-temperature state of the quantum spin liquid candidate κ-(BEDT-TTF)2Cu2(CN)3 emerges via an anomaly at T∗∼6 K. Although signatures of this anomaly have been revealed in various quantities, its origin has remained unclear. Here we report inelastic neutron scattering measurements on single crystals of κ-(BEDT-TTF)2Cu2(CN)3, aiming at studying phonon renormalization effects at T∗. A drastic change was observed in the phonon damping across T∗ for a breathing mode of BEDT-TTF dimers at E=4.7 meV. The abrupt change in the phonon damping is attributed to a phase transition into a valence bond solid state based on an effective model describing the spin-charge coupling in this dimer-Mott system. © 2022 authors. Published by the American Physical Society.
