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

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, comprising alternating and ferrimagnet-like types that can be induced and manipulated by an electric field. A symmetry framework based on 464 collinear spin layer groups is established to systematically classify chiral splitting characteristics and their electric-field responses in two-dimensional magnets. We elucidate how the spin layer group dictates the nodal structure of alternating chiral splitting and identify the lowest-order magnetic exchange interaction driving this chiral splitting. We demonstrate electric-field control over the magnitude and sign of the chiral splitting, enabling reversible switching of the spin Seebeck and Nernst effects. This work provides a general theory for electric-field manipulation of magnon chirality and paves the way for the development of low-power magnonic logic devices.