Interplay of topology and geometry in frustrated 2d Heisenberg magnets

Abstract

We investigate two-dimensional frustrated Heisenberg magnets using non-perturbative renormalization group techniques. These magnets allow for point-like topological defects which are believed to unbind and drive either a crossover or a phase transition which separates a low temperature, spin-wave dominated regime from a high temperature regime where defects are abundant. Our approach can account for the crossover qualitatively and both the temperature dependence of the correlation length as well as a broad but well defined peak in the specific heat are reproduced. We find no signatures of a finite temperature transition and an accompanying diverging length scale. Our analysis is consistent with a rapid crossover driven by topological defects.

12 pages, 8 figures, final version to appear in Physical Review B

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• Topological Transition to a Critical Phase in a Two-dimensional 3-Vector Model with non-Abelian Fundamental Group: A Simulational Study