Tunable Magnonic Chern Bands and Chiral Spin Currents in Magnetic Multilayers

TL;DR

This paper demonstrates that magnetic multilayers with antiparallel alignment can host tunable topological magnonic surface states with chiral spin currents, promising low-power spintronic applications.

Contribution

It introduces a magnetic multilayer system where dipolar interactions produce topological magnonic bands and surface states, tunable via external magnetic fields.

Findings

Bulk bands with non-zero Chern numbers are generated.

Chiral surface spin currents are localized and controllable.

The system enables low-dissipation, tunable spin current transport.

Abstract

Realization of novel topological phases in magnonic band structures represents a new opportunity for the development of spintronics and magnonics with low power consumption. In this work, we show that in antiparallelly aligned magnetic multilayers, the long-range, chiral dipolar interaction generates bulk bands with non-zero Chern integers and magnonic surface states carrying chiral spin currents. The surface states are strictly localized and can be easily toggled between non-trivial and trivial phases through an external magnetic field. The realization of chiral surface spin currents in this dipolarly coupled heterostructure represents a magnonic implementation of the coupled wire model that has been extensively explored in electronic systems. Our work presents an easy-to-implement system for realizing topological magnonic surface states and low-dissipation spin current transport in a tunable manner.