Tunable topological magnon-polaron states and anomalous Hall phenomena in two-dimensional ferromagnetic insulators

TL;DR

This paper explores tunable topological magnon-polaron states in 2D ferromagnetic insulators, demonstrating control over anomalous Hall effects via magnetic field manipulation, revealing new quantum geometrical phenomena.

Contribution

It introduces a method to tune Chern numbers and Berry curvatures of magnon-polaron bands through magnetic field orientation, enabling control over Hall responses.

Findings

Magnetic field direction can suppress thermal Hall signals.

Magnon-polaron states exhibit tunable topological properties.

Control over spin Nernst signals is achieved.

Abstract

We study magnon-polaron hybrid states, mediated by Dzyaloshinskii-Moriya and magnetoelastic interactions, in a two-dimensional ferromagnetic insulator. The magnetic system consists of both in-plane and flexural acoustic and optical phonon bands, as well as acoustic and optical magnon bands. Through manipulation of the ground-state magnetization direction using a magnetic field, we demonstrate the tunability of Chern numbers and (spin) Berry curvatures of magnon-polaron hybrid bands. This adjustment subsequently modifies two anomalous Hall responses of the system, namely, thermal Hall and spin Nernset signals. Notably, we find that by changing the magnetic field direction in particular directions, it is possible to completely suppress the thermal Hall signal while maintaining a finite spin Nernst signal. Our finding reveals the intricate interplay between topological and quantum geometrical phenomena and magnetic ordering, offering compelling avenues for on-demand control over emergent quantum states in condensed matter systems.