Excitation Spectrum and Spin Hamiltonian of the Frustrated Quantum Ising Magnet Pr${}_3$BWO${}_9$

Abstract

We present a thorough experimental investigation on single crystals of the rare-earth based frustrated quantum antiferromagnet Pr${}_3$BWO${}_9$, a purported spin-liquid candidate on the breathing kagome lattice. This material possesses a disordered ground state with an unusual excitation spectrum involving a coexistence of sharp spin-waves and broad continuum excitations. Nevertheless, we show through a combination of thermodynamic, magnetometric and spectroscopic probes with detailed theoretical modeling that it should be understood in a completely different framework. The crystal field splits the lowest quasi-doublet states into two singlets moderately coupled through frustrated superexchange, resulting in a simple effective Hamiltonian of an Ising model in a transverse magnetic field. While our neutron spectroscopy data do point to significant correlations within the kagome planes, the dominant interactions are out-of-plane, forming frustrated triangular spin-tubes through two competing ferro-antiferromagnetic bonds. The resulting ground state is a simple quantum paramagnet, but with significant modifications to both thermodynamic and dynamic properties due to small perturbations to the transverse field Ising model in the form of hyperfine enhanced nuclear moments and weak structural disorder.

21 pages, 12 figures

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Cited by in corpus (11)

• Antiferromagnetic ordering and critical behavior induced giant magnetocaloric effect in distorted kagome lattice Gd${}_3$BWO${}_9$
• Induced quantum magnetism on a triangular lattice of non-Kramers ions in PrMgAl11O19
• Braided Ising spin-tube physics in a purported kagome magnet
• Magnetic properties and field-induced phenomena in the Jeff = 1/2 distorted kagome antiferromagnet
• Gapless spinon excitations emerging from a multipolar transverse field in the triangular-lattice Ising antiferromagnet NaTmSe2
• Crystal-Field--Driven Magnetoelectric Coupling in the Non-Kramers Hexaaluminate PrMgAl11O19
• Theory of magnetism for rare-earth magnets on the Shastry-Sutherland lattice with non-Kramers ions
• Ising Supercriticality and Universal Magnetocalorics in Spiral Antiferromagnet Nd${}_3$BWO${}_9$
• Spin-liquid-like spin dynamics in the frustrated antiferromagnet TbBO3
• Magnetic and thermodynamic studies on the distorted kagome magnet Pr${}_3$BWO${}_9$
• Z${}_2$ topological orders in kagomé dipolar systems: Feedback from Rydberg quantum simulator