Regensburg 2022 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 23: Frustrated Magnets - General
TT 23.10: Vortrag
Mittwoch, 7. September 2022, 17:30–17:45, H22
Towards analyzing phase-transitions with continuous similarity transformation: Easy-axis square-lattice XXZ and J1-J2 models — •Matthias R. Walther1, Dag-Björn Hering2, Götz S. Uhrig2, and Kai P. Schmidt1 — 1Friedrich-Alexander-Universität Erlangen-Nürnberg, Institut für Theoretische Physik I, Staudtstraße 7, 91058 Erlangen — 2Technische Universität Dortmund, Department of Physics, Condensed Matter Theory, Otto-Hahn-Str. 4, 44227 Dortmund
The method of non-perturbative continuous similarity transformations (CST) in momentum space captures the physics of the isotropic spin 1/2 antiferromagnetic Heisenberg model on the square lattice (IHM) quantitatively [1,2]. We discuss the potential of the CST to study critical behavior. To this end, the easy-axis square-lattice XXZ-model serves as a straight-forward extension of the IHM with a gapped phase away from the isotropic point. Its critical behavior is described by an established mean-field theory [3]. The CST is able to capture this criticality quantitatively. For further insights on the general capability of the CST for spin models we extend the study towards the frustrated square-lattice spin 1/2 antiferromagnetic J1-J2 model and analyze the breakdown of the magnetically ordered quantum phases and their gapless spin wave excitations [4,5].
[1] M. Powalski et al., Rev. Lett. 115, 207202 (2015)
[2] M. Powalski et al., SciPost Phys. 4, 001 (2018)
[3] W. Zheng et al., Phys. Rev. B 71, 184440 (2005)
[4] Götz S. Uhrig et al., Phys. Rev. B 79, 092416 (2009)
[5] R. R. P. Singh et al., Phys. Rev. Lett. 91, 017201 (2003)