Composite Spin Crystal Phase in Antiferromagnetic Chiral Magnets

TL;DR

This paper investigates a complex antiferromagnetic spin crystal phase in chiral magnets, explicitly constructing an effective action to understand its properties and potential interactions with other physical phenomena.

Contribution

The paper provides an explicit low-energy effective action for the antiferromagnetic skyrmion lattice phase, facilitating further studies on its coupling to charge, lattice, and disorder effects.

Findings

Identification of a composite skyrmion lattice phase in antiferromagnetic chiral magnets

Construction of a low-energy effective action capturing the phase's phenomenology

Foundation for studying interactions with charge carriers and disorder

Abstract

We study the classical antiferromagnetic Heisenberg model on the triangular lattice with Dzyaloshinskii-Moriya interactions in a magnetic field. We focus in particular in the emergence of a composite spin crystal phase, dubbed antiferromagnetic skyrmion lattice, that was recently observed in [Phys. Rev. B 92, 214439 (2015)] for intermediate fields. This complex phase can be made up from three inter-penetrated skyrmion lattices, one for each sub-lattice of the original triangular one. Following these recent numerical results, in this paper we explicitly construct the low-energy effective action that reproduces the correct phenomenology and could serve as a starting point to study the coupling to charge carriers, lattice vibrations, structural disorder and transport phenomena.