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arXiv · 0909.3355

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

A. Zheludev·V. O. Garlea·A. Tsvelik·L. -P. Regnault·K. Habicht·K. Kiefer·B. Roessli
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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.

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A. Zheludev, V. O. Garlea, A. Tsvelik, L. -P. Regnault, K. Habicht, K. Kiefer, B. Roessli. 2009-09-18. Excitations from a chiral magnetized state of a frustrated quantum spin liquid. https://doi.org/10.1103/physrevb.80.214413

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