Chiral Spin Liquid in two-dimensional XY Helimagnets

TL;DR

This paper uses Monte-Carlo simulations to explore phase transitions in a 2D XY helimagnet, revealing a chiral spin liquid phase between Ising and BKT transition lines.

Contribution

It identifies a chiral spin liquid phase in a 2D XY helimagnet, characterized by two successive phase transitions, which was not previously demonstrated in this context.

Findings

Discovery of a chiral spin liquid phase between Ising and BKT transitions.

Identification of two successive phase transitions: Z_2 symmetry breaking and BKT transition.

Confirmation of the phase diagram structure through Monte-Carlo simulations.

Abstract

We carry out Monte-Carlo simulations to discuss critical properties of a classical two-dimensional XY frustrated helimagnet on a square lattice. We find two successive phase transitions upon the temperature decreasing: the first one is associated with breaking of a discrete Z_2 symmetry and the second one is of the Berezinskii-Kosterlitz-Thouless (BKT) type at which the SO(2) symmetry breaks. Thus, a narrow region exists on the phase diagram between lines of the Ising and the BKT transitions that corresponds to a chiral spin liquid.