Regensburg 2013 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 7: Correlated Electrons: Spin Systems, Itinerant Magnets 1
TT 7.6: Vortrag
Montag, 11. März 2013, 10:45–11:00, H19
Z2-vortex phase in a triangular-lattice Kitaev-Heisenberg model: Numerical simulations — Ioannis Rousochatzakis, Ulrich K. Rössler, Jeroen van den Brink, and •Maria Daghofer — IFW Dresden
We present numerical evidence for a Z2-vortex phase in the triangular-lattice Kitaev-Heisenberg model. We performed unbiased Monte-Carlo simulations
and found at least two incommensurate phases: One of them is dominated
by three incommensurate ordering vectors, one for each spin
component, Sx, Sy and Sz. This phase hosts localized defects that are
similar to skyrmions, but are here identified as Z2 vortices. The
vortices are seen to form regular lattices that optimize their distance
and whose lattice constant is determined by the incommensurate
ordering vectors. For very large
spin-orbit coupling, a different incommensurate phase emerges, where
the symmetry between the three lattice directions (and spin
components) is broken. One spin component dominates here and finite
temperatures are characterized by nearly decoupled antiferromagnetic
Ising chains, as in the square-lattice compass model. Connections to
models for iridates will also be discussed.
[1] I. Rousochatzakis, U. K. Rössler, J. van den Brink, M. Daghofer,
arXiv:1209.5895