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Kitaev anisotropy induces mesoscopic Z2 vortex crystals in frustrated hexagonal antiferromagnets

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journal contribution
posted on 06.08.2018, 15:29 by Ioannis RousochatzakisIoannis Rousochatzakis, Ulrich K. Roessler, Jeroen van den Brink, Maria Daghofer
The triangular-lattice Heisenberg antiferromagnet (HAF) is known to carry topological Z2 vortex excitations which form a gas at finite temperatures. Here we show that the spin-orbit interaction, introduced via a Kitaev term in the exchange Hamiltonian, condenses these vortices into a triangular Z2 vortex crystal at zero temperature. The cores of the Z2 vortices show abrupt, soliton-like magnetization modulations and arise by a special intertwining of three honeycomb superstructures of ferromagnetic domains, one for each of the three sublattices of the 120 state of the pure HAF. This is an example of a nucleation transition, analogous to the spontaneous formation of magnetic domains, Abrikosov vortices in type-II superconductors, blue phases in cholesteric liquid crystals, and skyrmions in chiral helimagnets. As the mechanism relies on the interplay of geometric frustration and spin-orbital anisotropies, such vortex mesophases can materialize as a ground state property in spin-orbit coupled correlated systems with nearly hexagonal topology, as in triangular or strongly frustrated honeycomb iridates.

Funding

This research was sponsored by the Deutsche Forschungsgemeinschaft (DFG) under the Emmy-Noether Program (1235/1).

History

School

  • Science

Department

  • Physics

Published in

Physical Review B

Volume

93

Issue

10

Citation

ROUSOCHATZAKIS, I. ... et al, 2016. Kitaev anisotropy induces mesoscopic Z2 vortex crystals in frustrated hexagonal antiferromagnets. Physical Review B, 93 (10), 104417.

Publisher

© American Physical Society

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2016-03-17

Notes

This paper was published in the journal Physical Review B and the definitive published version is available at https://doi.org/10.1103/PhysRevB.93.104417.

ISSN

2469-9950

eISSN

2469-9969

Language

en

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