Research: Experimental observation of repulsively bound magnons

Together with colleagues from Augsburg, Bonn, Cologne, Dresden, Geneva and Prince George (Canada), Prof. Zhe Wang from the Faculty of Physics at TU Dortmund University has experimentally proved the existence of repulsively bound magnons in  the Ising-like spin chain antiferromagnet BaCo₂V₂O₈. To study spin dynamics in magnetic fields of up to 60 T, we used a combination of the free electron laser at the Helmholtz-Zentrum Dresden-Rossendorf and a pulsed-field magnet  at the Hochfeld-Magnetlabor Dresden.  We identify repulsively bound magnon states by comparing results of  terahertz spectroscopy measurements to theoretical results for the Heisenberg–Ising chain antiferromagnet. The experimental results show that these high-energy, repulsively bound magnon states are well separated from continua, exhibiting  notable dynamical responses and, despite dissipation, are sufficiently long-lived to be observed experimentally.

Z. Wang, C.-M. Halati, J.-S. Bernier, A.  Ponomaryov, D. I. Gorbunov, S. Niesen, O. Breunig, J. M.  Klopf, S.  Zvyagin, T.  Lorenz, A.  Loidl, C. Kollath,
Experimental observation of repulsively bound magnons,
Nature 631, 760 (2024)