A General Theory of Chiral Splitting of Magnons in Two-Dimensional Magnets

TL;DR

This paper develops a comprehensive symmetry-based theory for controlling magnon chirality in two-dimensional magnets using electric fields, enabling advances in magnonic logic and spintronic devices.

Contribution

It introduces the concept of extrinsic chiral splitting controlled by electric fields and classifies it using a symmetry framework based on 464 collinear spin layer groups.

Findings

Electric fields can modulate the magnitude and sign of magnon chiral splitting.

The symmetry framework predicts the type of chiral splitting and dominant exchange interactions.

Electric control influences thermal spin transport phenomena like the spin Seebeck and Nernst effects.

Abstract

Magnons in antiferromagnets exhibit two chiral modes, providing an intrinsic degree of freedom for magnon-based computing architectures and spintronic devices. Electrical control of chiral splitting is crucial for applications, but remains challenging. Here, we propose the concept of extrinsic chiral splitting, involving alternating and ferrimagnet-like types, which can be induced and controlled by an electric field. A symmetry framework based on 464 collinear spin layer groups is established to classify chiral splitting characteristics and electric field responses in two-dimensional magnets. We further elucidate how the spin layer group determines the type of alternating chiral splitting and the dominant lowest-order magnetic exchange interaction. We demonstrate electric-field control over the magnitude and sign of the chiral splitting, enabling control of the spin Seebeck and Nernst effects related to thermal spin transport. This work provides a general theory for electric field manipulation of magnon chirality, paving the way for low-power magnonic logic devices.