Quantum spin dynamics of quasi-one-dimensional Heisenberg-Ising magnets in a transverse field: confined spinons, E8 spectrum, and quantum phase transitions

We report on high-resolution terahertz spectroscopic studies of quantum spin dynamics in the quasi-one-dimensional Ising-like ferromagnet CoNb2O6 and antiferromagnet BaCo2V2O8 as a function of an applied transverse magnetic field. In the ordered phases stabilized by inter-chain couplings, we reveal characteristics for confined spinon excitations, E-8 dynamical spectrum, and field-induced quantum phase transitions. The connections between these characteristic dynamical features are found in the field-dependent evolution of the excitation spectra.

Automated summary

In this study, high-resolution terahertz spectroscopic techniques were used to investigate the quantum spin dynamics in the quasi-one-dimensional Ising-like ferromagnet CoNb2O6 and antiferromagnet BaCo2V2O8. Confined spinon excitations, E-8 dynamical spectrum, and field-induced quantum phase transitions were observed in the ordered phases stabilized by inter-chain couplings, with the field-dependent evolution of the excitation spectra revealing connections between these characteristic dynamical features.