For quasi-one dimensional quantum spin systems theory predicts the occurrence of a confinement of spinon excitation due to interchain couplings. Here we investigate the system SrCo2V2O8, a realization of the weakly-coupled Ising-like XXZ antiferromagnetic chains, by terahertz spectroscopy with and without applied magnetic field. At low temperatures a series of excitations is observed, which split in a Zeeman-like fashion in an applied magnetic field. These magnetic excitations are identified as the theoretically predicted spinon-pair excitations. Using a one dimensional Schr\"odinger equation with a linear confinement potential imposed by weak interchain couplings, the hierarchy of the confined spinons can be fully described.
@article{arxiv.1503.06351,
title = {Spinon Confinement in the One-Dimensional Ising-Like Antiferromagnet SrCo2V2O8},
author = {Zhe Wang and M. Schmidt and A. K. Bera and A. T. M. N. Islam and B. Lake and A. Loidl and J. Deisenhofer},
journal= {arXiv preprint arXiv:1503.06351},
year = {2015}
}