arXiv:cond-mat/0207187 · Physical review. B, Condensed matter
Chiral critical behavior of frustrated spin systems in two dimensions from five-loop renormalization-group expansions
Pasquale Calabrese, E. V. Orlov, Pietro Parruccini, Aleksandr Ivanovich Sokolov
Abstract
We analyze the critical behavior of two-dimensional N-vector spin systems with noncollinear order within the five-loop renormalization-group (RG) approximation. The structure of the RG flow is studied for different N leading to the conclusion that the chiral fixed point governing the critical behavior of physical systems with $N=2$ and $N=3$ does not coincide with that given by the $1/N$ expansion. We show that the stable chiral fixed point for $N<~{N}^{*},$ including $N=2$ and $N=3,$ turns out to be a focus. We give a complete characterization of the critical behavior controlled by this fixed point, also evaluating the subleading crossover exponents. The spiral-like approach of the chiral fixed point is argued to give rise to unusual crossover and near-critical regimes that may imitate varying critical exponents seen in numerous physical and computer experiments.