Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 23: Correlated Electrons – Poster I
TT 23.11: Poster
Monday, March 9, 2026, 18:00–20:00, P1
Quantum effects in the magnon spectrum of 2D altermagnets on a square lattice and anisotropic honeycomb lattice via continuous similarity transformations. — •Dag-Björn Hering1, Vanessa Sulaiman1, Raymond Wiedmann3, Matthias R. Walther2, Götz S. Uhrig1, and Kai P. Schmidt2 — 1Condensed Matter Theory, Technische Universität Dortmund, Otto-Hahn-Straße 4, 44221 Dortmund, Germany — 2Department of Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany — 3Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569, Stuttgart, Germany
We investigate quantum effects on magnon excitations in a minimal spin-1/2 Heisenberg model for 2D altermagnets on the square lattice and for an anisotropic honeycomb lattice. For both, a continuous similarity transformation is applied in momentum space to derive an effective Hamiltonian that conserves the number of magnon excitations. This allows us to quantitatively calculate the one-magnon dispersion, the effects of magnon-magnon interactions, and the dynamic structure factor in a certain range of parameters. For the altermagnet, we focus on the altermagnetic spin splitting of the magnon bands and the size of the roton minimum. For the honeycomb, we additionally analyze the ground state energy and the staggered magnetization. We further analyze the stability of the assumed long-range order and the magnons by different generators.
Keywords: Continuous Similarity Transformation; Altermagnetism; Anisotropic XXZ Model; Antiferromagnetism; Honeycomb Lattice