Universal Berezinskii-Kosterlitz-Thouless dynamic scaling in the intermediate time range in frustrated Heisenberg antiferromagnets on a triangular lattice

We investigate nonequilibrium properties of the frustrated Heisenberg antiferromagnets on the triangular lattice. Nonequilibrium critical relaxation of frustrated Heisenberg antiferromagnets shows a dynamic transition (or, at least, sharp crossover) near the temperature ${T}_{\mathrm{u}}=0.282J$ of the equilibrium ${\mathbb{Z}}₂$-vortex unbinding. We show that starting from the high-temperature initial state, due to the presence of ${\mathbb{Z}}₂$ vortices in the system being considered, in a broad temperature range $T<{T}_{\mathrm{u}}$ the dynamic properties in the intermediate time range are similar to those of the two-dimensional XY model below the Berezinskii-Kosterlitz-Thouless transition. The interaction of ${\mathbb{Z}}₂$ vortices with spin-wave degrees of freedom does not emerge until rather long times.