From Skyrmion Antiferromagnetic Cristal to $Z_2$-vortex lattice

H. D. ROSALES; D. C. CABRA; M. B. STURLA; S. A. OSORIO

Trieste

Conferencia; Quantum Dynamics of Disordered Interacting Systems; 2018

International Center for Theoretical Physics; ICTP

We study the classical antiferromagnetic Heisenberg model on the triangular lattice with Dzyaloshinskii-Moriya interactions in a magnetic field. The effective theory for the spins on each sublattice is similar to those observed in chiral ferromagnets and presents a complex phase for intermediate fields. The corresponding spin texture can be made up from three interpenetrated skyrmion lattices, one for each sublattice of the original triangular one. We focus in particular on this composite spin crystal phase and construct an $SO(3)$ theory for the order parameter. This approach reveals the presence of pairs of $Z_2$ vortices