Dresden 2017 – scientific programme
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MA: Fachverband Magnetismus
MA 48: Spin Dynamics and Transport: Spin Excitations and Spin Torque Phenomena
MA 48.13: Talk
Thursday, March 23, 2017, 12:45–13:00, HSZ 101
Quantum spin dynamics in a spin-1/2 antiferromagnetic Heisenberg-Ising chain — •Zhe Wang1,2, Anup Kumar Bera3, Nazmul Islam3, Bella Lake3, Joachim Deisenhofer2, and Alois Loidl2 — 1Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2University of Augsburg, Augsburg, Germany — 3Helmholtz-Zentrum Berlin, Berlin, Germany
Emergent states of matter in quantum magnets are characterized by their elementary magnetic excitations that can be induced and tuned in an external magnetic field. We report on terahertz spectroscopy of elementary excitations in a spin-1/2 Heisenberg-Ising antiferromagnetic chain as a function of temperature and magnetic field. At zero field confined spinon excitations are observed below the Néel temperature [1]. Emergent ferminonic excitations are observed in a transverse magnetic field [2], when the confinement is suppressed and an order-disorder phase transition is induced. In the longitudinal fields, the high-energy string excitations are observed in addition to the low energy spin exciations. These experimental results are understood by comparison to precise calculation of dynamic structure factors by the method of infinite time evolving block decimation and using Bethe ansatz for the transverse and longitudinal fields, respectively.
In collaboration with Hans Engelkamp, Papori Gogoi, Dmytro Kamenskyi, Michael Schmidt, Nanlin Wang, Congjun Wu, Jianda Wu, Shenglong Xu, Wang Yang.
[1]Zhe Wang et al. Phys. Rev. B 91, 140404(R) (2015). [2]Zhe Wang et al. Phys. Rev. B 94, 125130 (2016).