Excitations from a chiral magnetized state of a frustrated quantum spin liquid

Abstract

We study excitations in weakly interacting pairs of quantum spin ladders coupled through geometrically frustrated bonds. The ground state is a disordered spin liquid, that at high fields is replaced by an ordered chiral helimagnetic phase. The spectra observed by high-field inelastic neutron scattering experiments on the prototype compound Sul-Cu2Cl4 are qualitatively different from those in the previously studied frustration-free spin liquids. Beyond the critical field Hc=3.7 T, the soft mode that drives the quantum phase transition spawns two separate excitations: a gapless Goldstone mode and a massive magnon. Additional massive quasiparticles are clearly visible below Hc, but are destroyed in the ordered phase. In their place one observes a sharply bound excitation continuum.

6 pages, 4 figures

References in corpus (4)

• Bose-Einstein Condensation in Magnetic Insulators
• Excitations from a Bose-Einstein condensate of magnons in coupled spin ladders
• Dimensional crossover in a spin liquid to helimagnet quantum phase transition
• Low-energy excitations in the magnetized state of the bond-alternating quantum S=1 chain system NTENP

Cited by in corpus (7)

• Electron Spin Resonance in Quasi-One-Dimensional Quantum Antiferromagnets: Relevance of Weak Interchain Interactions
• Crystals for neutron scattering studies of quantum magnetism
• Disorder instability of the magnon condensate in a frustrated spin ladder
• Magnetic-field induced multiferroicity in a quantum critical frustrated spin liquid
• Double zigzag spin chain in strong magnetic field close to saturation
• Giant dielectric nonlinearities at a magnetic Bose-Einstein condensation
• Magnetic resonance of collective paramagnets with gapped excitations spectrum