Dresden 2017 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 17: PhD Symposium: Quantum Magnets: Frustration and Topology in Experiment and Theory (jointly with Young DPG (jDPG)

MA 17.3: Hauptvortrag

Dienstag, 21. März 2017, 11:30–12:00, HSZ 04

Effects of anisotropic exchange in strong spin-orbit coupled magnets — •Natalia Perkins — University of Minnesota, Minneapolis, USA

Recently, the Jackeli-Khaliullin Kitaev (JKK) materials on various two- and three-dimensional tri-coordinated lattices, which are believed to be proximate to the Kitaev Quantum spin liquid, have attracted a lot of attention. In all these materials, the geometry of the lattices with edge-sharing octahedra of ligand ions is such that it gives rise to the dominant Kitaev interactions between effective j=1/2 magnetic moments of the transition metal ions. Nevertheless, the experimental studies of the JKK materials have shown that at sufficiently low temperatures and ambient pressure all of them order magnetically. These findings suggest that experimentally relevant super-exchange models must contain other subdominant interactions between magnetic moments in addition to the Kitaev coupling. In my talk I will discuss the effects of these anisotropies. I will show that the Kitaev spin liquid is very fragile with respect to the both second neighbor Kitaev interaction and the off-diagonal symmetric exchange anisotropy. I will also show that the off-diagonal exchange anisotropy drives the model to a classical spin liquid phase, characterized by an extensive number of ground states and ultra-short, highly anisotropic spin-spin correlations.