Dresden 2026 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 98: Altermagnets
TT 98.7: Talk
Friday, March 13, 2026, 11:15–11:30, CHE/0091
Nonlinear Sigma Model of an Insulating Altermagnet — •Parasar Thulasiram1,2, Chris Hooley3, and Roderich Moessner1 — 1Max Planck Institute for the Physics of Complex Systems, Dresden, Germany — 2Max Planck Institute for Chemical Physics of Solids, Dresden, Germany — 3Centre for Fluid and Complex Systems, Coventry University, Coventry, United Kingdom
We applied the Haldane map to derive an O(3) x O(3) nonlinear sigma model of an insulating altermagnet from a transition-metal-dichalcogenide-inspired 3D spin model. The model displays nonrelativistic spin splitting of the magnon bands and anisotropic couplings. We studied the energetics of its preferred topological defects (skyrmions and hopfions), their viability in being generated, as well as the model's behaviour under lightly frustrated couplings. We performed a renormalization analysis of the model and studied its (in)stabilities.
Keywords: Altermagnets; Nonlinear Sigma Model; Unconventional Magnetism; Field Theory; Topological Defects