Nonequilibrium selection of magnetic order in driven triangular XY antiferromagnet

TL;DR

This paper demonstrates how a weak periodic drive can select a specific magnetic order in a driven triangular XY antiferromagnet, leading to a non-equilibrium phase transition that can be experimentally realized without complex setups.

Contribution

It introduces a novel mechanism where periodic driving lifts degeneracy in a magnetic system, competing with thermal effects to induce phase transitions.

Findings

Periodic drive removes ground state degeneracy.

Effective potential generated for pseudo-Goldstone mode.

Non-equilibrium phase transition observed with temperature tuning.

Abstract

We show that a weak periodic drive removes the accidental degeneracy in the ground state of the XY antiferromagnet on the triangular lattice in a uniform static magnetic field. The underlying mechanism involves adding a small periodically modulated component to the magnetic field, which influences finite-frequency modes to generate an effective potential for the accidental pseudo-Goldstone mode. This selection can be arranged to compete with the degeneracy lifting via the thermal order by disorder mechanism. This yields a non-equilibrium phase transition as the relative strength of the two mechanisms is tuned by varying temperature. This proposal may be amenable to experimental realization, in particular as applying the field is noninvasive, and no complex bath engineering is required.