Antiferromagnetic Skyrmion Crystals in the Rashba Hund's Model on Triangular Lattice

TL;DR

This paper investigates antiferromagnetic skyrmion crystal states in a spin-orbit coupled model on a triangular lattice, revealing two distinct phases stabilized by magnetic fields and their experimental signatures.

Contribution

It introduces a theoretical and computational framework for stabilizing and distinguishing two antiferromagnetic skyrmion crystal phases in a Rashba Hund's model on a triangular lattice.

Findings

Two AF-SkX states are stabilized at low temperatures with magnetic field.

Distinct peaks in spin structure factor differentiate the phases.

Potential material realizations are discussed.

Abstract

Motivated by the importance of antiferromagnetic skyrmions as building blocks of next-generation data storage and processing devices, we report theoretical and computational analysis of a model for a spin-orbit coupled correlated magnet on a triangular lattice. We find that two distinct antiferromagnetic skyrmion crystal (AF-SkX) states can be stabilized at low temperatures in the presence of external magnetic field. The results are obtained via Monte Carlo simulations on an effective magnetic model derived from the microscopic electronic Hamiltonian consisting of Rashba spin-orbit coupling, as well as the Hund's rule coupling of electrons to large classical spins. The two AF-SkX phases are understood to originate from a classical spin liquid state that exists at low but finite temperatures. These AF-SkX states can be easily distinguished from each other in experiments as they are characterized by peaks at distinct momenta in the spin structure factor which is directly measured in neutron scattering experiments. We also discuss examples of materials where the model as well as the two AF-SkX states can be realized.