arXiv:cond-mat/9711207 · Physical review. B, Condensed matter
Low-energy excitations and phase transitions in the frustrated two-dimensional XY model
Colin Denniston B, Chao Tang
Abstract
We study the critical properties of the two-dimensional (2D) $\mathrm{XY}$ model in a transverse magnetic field with filling factors $f=1/3$ and $2/5.$ To obtain a comparison with recent experiments, we investigate the effect of weak quenched bond disorder for $f=2/5.$ A finite-size scaling analysis of extensive Monte Carlo simulations strongly suggests that the critical exponents of the phase transition for $f=1/3$ and for $f=2/5$ with disorder are those of the pure 2D Ising model. The relevant low-energy excitations are domain walls, and we show that their properties determine the nature of the phase transition.