Electric polarization induced by magnons and magnon Nernst effects

TL;DR

This paper demonstrates that magnons can induce electric polarization in 2D antiferromagnets via their spin and orbital moments, especially with Dzyaloshinskii-Moriya interaction, enabling potential magnon detection and manipulation for future technologies.

Contribution

It introduces a theoretical framework showing how magnons induce electric polarization through spin and orbital moments, highlighting the role of DMI and symmetry in 2D materials.

Findings

Electric polarization by magnons depends on DMI presence.

Zigzag order yields much larger polarization than Ne9el order.

Magnon orbital moments significantly enhance electric polarization.

Abstract

Magnons offer a promising path toward energy-efficient information transmission and the development of next-generation classical and quantum computing technologies. However, methods to efficiently excite, manipulate, and detect magnons remain a critical need. Here, we show that magnons, despite their charge-neutrality, can induce electric polarization as a result of both their spin and orbital moments. We demonstrate this by calculating the electric polarization induced by magnons in two-dimensional (2D) honeycomb antiferromagnets. The electric polarization becomes finite when the Dzyaloshinskii-Moriya Interaction (DMI) is present and its magnitude can be increased by symmetries of the system. We illustrate this by computing and comparing the electric polarizations induced by the magnon Nernst effects in 2D materials with N\'eel and Zigzag ordering. Our findings show that in the Zigzag order, where the effect is dominated by the magnon orbital moment, the induced electric polarization is approximately three orders of magnitude greater than in the N\'eel phase. These findings reveal that electric fields could enable both detection and manipulation of magnons under certain conditions by leveraging their spin and orbital angular moment. They also suggest that the discovery or engineering of materials with substantial magnon orbital moments could lead to more practical use of magnons for future computing and information transmission device applications.