Signature of a $Z_{2}$ Vortex in the Dynamical Correlations of the Triangular-Lattice Heisenberg Antiferromagnet

概要

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Dynamical properties of the classical Heisenberg antiferromagnet on the triangular lattice are investigated by means of a spin-dynamics simulation and an analytical calculation. While the model was suggested to exhibit a topological transition driven by the $Z_{2}$-vortex binding–unbinding, weakness of the associated thermodynamic singularity has made it difficult to observe the evidence of the $Z_{2}$ vortex experimentally so far, only some indirect support. Here, we show that the signature of the $Z_{2}$-vortex excitation and the vortex-induced topological transition can be captured from the dynamical spin correlations. In particular, the dynamical spin structure factor exhibits a characteristic central peak around the $Z_{2}$-vortex transition, and this central peak will be a fingerprint of the $Z_{2}$-vortex excitation.
Physical Society of Japanの論文
2010-08-15