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

Abstract

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 Tu=0.282J of the equilibrium Z2-vortex unbinding. We show that starting from the high-temperature initial state, due to the presence of Z2 vortices in the system being considered, in a broad temperature range T<Tu 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 Z2 vortices with spin-wave degrees of freedom does not emerge until rather long times. © 2017 American Physical Society.