2019/09/30 by K. Aoyama, H. Kawamura · 1 citation
Physics and Astronomy · #cond-mat.str-el #cond-mat.stat-mech
paper · pdf · doi:10.1103/physrevlett.124.047202
published as Phys. Rev. Lett. 124, 047202 (2020) · 6 pages, 3 figures, Supplemental Material(9 pages, 2 figures)
arxiv created 2020/01/06 · arxiv updated 2020/01/31
We have theoretically investigated transport properties of the classical Heisenberg antiferromagnet on the triangular lattice in which a binding-unbinding topological transition of ℤ2 vortices is predicted to occur at a finite temperature Tv. It is shown by means of the hybrid Monte-Carlo and spin-dynamics simulations that the longitudinal spin-current conductivity exhibits a divergence at Tv, while the thermal conductivity only shows a monotonic temperature dependence with no clear anomaly at Tv. The significant enhancement of the spin-current conductivity is found to be due to the rapid growth of the spin-current-relaxation time toward Tv, which can be understood as a manifestation of the topological nature of the free ℤ2 vortex whose lifetime gets longer toward Tv. The result suggests that the spin-current measurement is a promising probe to detect the ℤ2-vortex topological transition which has remained elusive in experiments.