SKM 2023 – scientific programme
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MA: Fachverband Magnetismus
MA 9: Cooperative Phenomena: Spin Structures and Magnetic Phase Transitions
MA 9.2: Talk
Monday, March 27, 2023, 15:15–15:30, HSZ 401
Magnetic correlations in the presence of disorder in the Hubbard model — •Fabio Pablo Miguel Méndez-Córdoba1,2,3, Joseph Tindall4, Dieter Jaksch2,5, and Frank Schlawin2,3,6 — 1Departamento de Física, Universidad de Los Andes, A.A. 4976, Bogotá, Colombia — 2Universität Hamburg, Luruper Chaussee 149, Gebäude 69, D-22761 Hamburg, Germany — 3The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, Hamburg D-22761, Germany — 4Center for Computational Quantum Physics, Flatiron Institute, 162 5th Avenue, New York, NY 10010 — 5Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK — 6Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
By selectively modifying hopping integrals in the triangular Hubbard model at half filling [1], we show that it is possible to change the ground state's spin angular momentum magnetization. We further demonstrate that this change does not appear in the corresponding effective Heisenberg model. The latter does not predict any magnetic coherence between distant sites [2]. Instead, higher-order interactions are required to anticipate the symmetry breaking that leads to the lifting of the degeneracy present in the Heisenberg model. Our results can be understood as an extension of Lieb's theorem to non-bipartite lattices [3].
[1] J. Tindall, et al., Phys. Rev. Lett. 125, 137001 (2020). [2] J. Strecka, et al., Phys. Rev. B 105, 064420 (2022). [3] E. H. Lieb, Phys. Rev. Lett. 62, 1201 (1989).