Berlin 2024 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 17: Focus Session: Quantum Interactive Dynamics II (joint session DY/TT)
TT 17.9: Talk
Monday, March 18, 2024, 17:45–18:00, A 151
Theory of Two-Dimensional Nonlinear Spectroscopy for Correlated Magnons in Three-Dimensional Canted Antiferromagnets — •Wonjune Choi1,2, Daniel Schultz3, Jonas Habel1,2, Johannes Knolle1,2, and Yong Baek Kim3 — 1Technical University of Munich, Garching, Germany — 2Munich Center for Quantum Science and Technology, München, Germany — 3University of Toronto, Toronto, Canada
We investigate how nonlinear response functions can capture the correlated dynamics of magnons, a phenomenon beyond the reach of linear spin wave theory. A recent experiment on the S=5/2 canted antiferromagnet YFeO3 [Zhang et al., arXiv:2301.12555] observed puzzling second-order dynamical responses that cannot be explained by the Landau-Lifshitz-Gilbert simulation. Our key finding addresses this puzzle by revealing that the experimentally observed new signals result from the quantum correction of the ground state and the mode-mode couplings between the distinct magnon modes at the reduced Brillouin zone center. These many-body quantum effects, dynamically generated by three magnon interactions, originate from the Dzyaloshinskii-Moriya interaction responsible for the noncollinear antiferromagnetic order. Our work highlights the potential application of nonlinear spectroscopy as a promising experimental route to understanding intertwined dynamics among correlated magnons.
Keywords: magnon; nonlinear dynamics; two-dimensional spectroscopy; nonlinear spin wave theory