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arXiv:0812.2119 · Physical Review B

Coarsening dynamics of an antiferromagnetic XY model on the kagome lattice: Breakdown of critical dynamic scaling

Sangwoong Park, Bongsoo Kim, Sung Jong Lee

Published Jun 8, 2009• 0 citations
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Abstract

We find a breakdown of the critical dynamic scaling in the coarsening dynamics of an antiferromagnetic $XY$ model on the kagome lattice when the system is quenched from disordered states into the Kosterlitz-Thouless phases at low temperatures. There exist multiple growing length scales; the length scales of the average separation between fractional vortices are found to be not proportional to the length scales of the quasiordered domains. They are instead related through a nontrivial power-law relation. The length scale of the quasiordered domains (as determined from the optimal collapse of the correlation functions for the order parameter $\text{exp}[3i\ensuremath{\theta}(r)]$) does not follow a simple power-law growth but exhibits an anomalous growth with time-dependent effective growth exponent. The breakdown of the critical dynamic scaling is accompanied by unusual relaxation dynamics in the decay of the fractional $(3\ensuremath{\theta})$ vortices, where the decay of the vortex numbers is characterized by an exponential function of the logarithmic powers in time.

DOI
10.1103/physrevb.79.214406

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