Rational Control of Magnonic and Electronic Band Splittings

TL;DR

This paper demonstrates how targeted structural distortions via phonon modes can controllably modulate spin splitting in electronic and magnonic bands, using MnF$_2$ as a model system, revealing a new approach for spintronic control.

Contribution

It introduces a theoretical method to control non-relativistic spin splitting through specific phonon-induced structural distortions in antiferromagnetic materials.

Findings

Structural distortions modulate magnon and electronic spin splittings.

Phonon modes A$_{2u}$ and A$_{1g}$ influence spin splitting without affecting magnetic order.

Lattice changes affect ligand environment, controlling spin dynamics.

Abstract

We provide a theoretical demonstration of controllable non-relativistic spin splitting in both electronic and magnonic bands via targeted structural distortions tied to specific phonon modes. Using MnF$_2$ as a model system, we identify a $d$-wave magnon band splitting between magnon modes of specific handedness, directly correlated with the non-relativistic spin splitting observed in the electronic structure. Crucially, we show that structural distortions associated with the A$_{2u}$ and A$_{1g}$ phonon modes (8.52 and 9.74 THz) modulate these splittings without altering the antiferromagnetic order. The effect originates from changes in the nonmagnetic ligand environment, highlighting the key role of lattice degrees of freedom in governing spin dynamics. Our findings establish a novel route for structure-mediated control of spin splitting, opening possibilities for tunable magnonic and spintronic functionalities in antiferromagnetic materials.