Quantum Critical Dynamics of a Heisenberg-Ising Chain in a Longitudinal Field: Many-Body Strings versus Fractional Excitations
Quantum Critical Dynamics of a Heisenberg-Ising Chain in a Longitudinal Field: Many-Body Strings versus Fractional Excitations
Wang, Z.; Schmidt, M.; Loidl, A.; Wu, J.; Zou, H.; Yang, W.; Dong, C.; Kohama, Y.; Kindo, K.; Gorbunov, D. I.; Niesen, S.; Breunig, O.; Engelmayer, J.; Lorenz, T.
We report a high-resolution terahertz spectroscopic study of quantum spin dynamics in the antiferromagnetic Heisenberg-Ising spin-chain compound BaCo2V2O8 as a function of temperature and longitudinal magnetic field. Confined spinon excitations are observed in an antiferromagnetic phase below TN ≃ 5.5 K. In a field-induced gapless phase above Bc = 3.8 T, we identify many-body string excitations as well as low-energy fractional psinon/antipsinon excitations by comparing to Bethe-Ansatz calculations. In the vicinity of Bc, the high-energy string excitations are found to be dynamically dominant over the fractional excitations.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review Letters 123(2019), 067202
DOI: 10.1103/PhysRevLett.123.067202
Cited 34 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-28993