Curvature-driven homogeneous Dzyaloshinskii-Moriya interaction and emergent weak ferromagnetism in anisotropic antiferromagnetic spin chains

TL;DR

This paper reveals how geometrical curvature in anisotropic antiferromagnetic spin chains induces a homogeneous Dzyaloshinskii-Moriya interaction and weak ferromagnetism, offering new ways to tailor spintronic and magnonic device functionalities.

Contribution

It demonstrates that geometry-driven effects in achiral, anisotropic antiferromagnetic chains include a strong, linear curvature-induced Dzyaloshinskii-Moriya interaction and weak ferromagnetism, expanding fundamental understanding.

Findings

Curvature induces a homogeneous Dzyaloshinskii-Moriya interaction.

Anisotropy effects complement curvature effects and are linear in curvature.

Emergence of geometry-driven weak ferromagnetism in antiferromagnetic chains.

Abstract

Chiral antiferromagnets are currently considered for broad range of applications in spintronics, spin-orbitronics and magnonics. In contrast to the established approach relying on materials screening, the anisotropic and chiral responses of low-dimensional antifferromagnets can be tailored relying on the geometrical curvature. Here, we consider an achiral, anisotropic antiferromagnetic spin chain and demonstrate that these systems possess geometry-driven effects stemming not only from the exchange interaction but also from the anisotropy. Peculiarly, the anisotropy-driven effects are complementary to the curvature effects stemming from the exchange interaction and rather strong as they are linear in curvature. These effects are responsible for the tilt of the equilibrium direction of vector order parameters and the appearance of the homogeneous Dzyaloshinskii-Moriya interaction. The latter is a source of the geometry-driven weak ferromagnetism emerging in curvilinear antiferromagnetic spin chains. Our findings provide a deeper fundamental insight into the physics of curvilinear antiferromagnets beyond the $\sigma$-model and offer an additional degree of freedom in the design of spintronic and magnonic devices.