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TT: Fachverband Tiefe Temperaturen

TT 80: Correlated Electrons: Poster

TT 80.26: Poster

Thursday, March 21, 2024, 15:00–18:00, Poster E

Continuous similarity transformation for Antiferromagnetic Heisenberg model on a honeycomb lattice — •Dag-Björn Hering¹, Matthias R. Walther², Kai P. Schmidt², and Götz S. Uhrig¹ — ¹Technische Universität Dortmund, Department of Physics, Condensed Matter Theory, Otto-Hahn-Str. 4, 44227 Dortmund — ²Friedrich-Alexander-Universität Erlangen-Nürnberg, Institut für Theoretische Physik I, Staudtstraße 7, 91058 Erlangen

In [1,2] Sala et al. showed that YbCl3 realizes the antiferromagnetic spin 1/2 Heisenberg model on the honeycomb lattice by comparing neutron scattering results with linear and self-consistent spin wave theory. However, deviations of the experimental data to the spin wave theory results occurred, namely an anomaly in the one-magnon dispersion at the K-point and in features of the the two-magnon continuum. This suggests that a treatment beyond self-consistent spin wave theory is needed. Continuous similarity transformations (CSTs) quantitively reproduced neutron scattering results for the antiferromagnetic Heisenberg model on a square lattice [3,4,5], where 1/S expansions were not sufficient for quantitative results. Here, we apply to the (CSTs) spin 1/2 Heisenberg model on the honeycomb lattice. 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] Nat. Commun. 12, 171 (2021)

[2] Commun. Phys. 6, 234 (2023)

[3] Rev. Lett. 115, 207202 (2015)

[4] SciPost Phys. 4, 001 (2018)

[5] Phys. Rev. Res. , 013132 (2023)

Keywords: antiferromagnetic Heisenberg model; honeycomb lattice; spin wave theory; continuous similarity transformation