Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 26: Correlated Magnetism – Frustrated Systems
TT 26.7: Vortrag
Mittwoch, 19. März 2025, 11:15–11:30, H33
Continuous Similarity Transformations for the Easy-Axis XXZ Model on the Honeycomb Lattice — •Matthias R. Walther1, Dag-Björn Hering2, Vanessa Sulaiman2, Maximilian Bayer1, Götz S. Uhrig2, and Kai P. Schmidt1 — 1Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany — 2Condensed Matter Theory, Technische Universität Dortmund, Otto-Hahn-Straße 4, 44221 Dortmund, Germany
Neutron scattering experiments on YbCl3 show that it realizes the antiferromagnetic Heisenberg model on a honeycomb lattice [1]. While key features are captured by linear spin-wave theory (LSWT), a full dispersion cannot be reproduced. We apply continuous similarity transformations (CSTs) [2-4] to the easy-axis antiferromagnetic XXZ-model on the honeycomb lattice. This allows us to derive an effective model which takes the relevant magnon-magnon interactions beyond LSWT into account targeting a quantitative description of the single-particle properties. The CST flow equations are truncated in momentum space by the scaling dimension d so that all contributions with d≤ 2 are taken into account. The resulting quartic magnon-conserving effective Hamiltonian is analyzed in the zero-, one-, and two-magnon sector.
[1] G. Sala et al., Nat. Comm. 12, 171 (2021).
[2] M.R. Walther et al., Phys. Rev. Res., 013132 (2023).
[3] M. Powalski et al., Rev. Lett. 115, 207202 (2015).
[4] M. Powalski et al., SciPost Phys. 4, 001 (2018).