SKM 2023 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 33: Frustrated Magnets I

MA 33.8: Vortrag

Mittwoch, 29. März 2023, 17:00–17:15, HSZ 403

Emergent U(1) symmetry due to off-diagonal symmetric exchange interactions — •Sagar Ramchandani, Ciarán Hickey, and Simon Trebst — Institute for Theoretical Physics, University of Cologne, Germany

Frustrated magnetic systems are a result of competing interactions. These systems are of interest as they can exhibit a large ground state degeneracy, sometimes in the form of an emergent symmetry for the ground state.

Here, we study the effects of off-diagonal symmetric exchange interactions on classical O(3) spins on the Kagome lattice. We find an emergent U(1) symmetry in the ground state. We study the critical properties and the influence of thermal order-by-disorder on this symmetry using a combination of analytical and Monte Carlo methods.

The symmetry can be understood on the level of a single triangle. Using this understanding, we also propose a set of rules to generate a lattice model with these off-diagonal interactions that will exhibit the same emergent U(1) symmetry. The rules combine N triangles exhibiting N*U(1) symmetries into a single U(1) symmetry. These lattices can be generated in 1D, 2D & 3D.