Electric field switching of altermagnetic spin-splitting in multiferroic skyrmions

TL;DR

This paper reports the discovery of electric field-controlled altermagnetic spin-splitting in multiferroic skyrmions within BiFeO3, enabling potential low-power, magnetoelectric applications in advanced computing.

Contribution

It demonstrates the electric field switching of altermagnetic spin-splitting in BiFeO3 skyrmions, a novel phenomenon in multiferroic materials with topological properties.

Findings

BiFeO3 can host Neel-type skyrmions at room temperature.

Altermagnetic spin splitting can be reversed by an electric field.

Skyrmions exhibit potential for low-power, magnetoelectric devices.

Abstract

Magnetic skyrmions are localized magnetic structures that retain their shape and stability over time, thanks to their topological nature. Recent theoretical and experimental progress has laid the groundwork for understanding magnetic skyrmions characterized by negligible net magnetization and ultrafast dynamics. Notably, skyrmions emerging in materials with altermagnetism, a novel magnetic phase featuring lifted Kramers degeneracy-have remained unreported until now. In this study, we demonstrate that BiFeO3, a multiferroic renowned for its strong coupling between ferroelectricity and magnetism, can transit from a spin cycloid to a Neel-type skyrmion under antidamping spin-orbit torque at room temperature. Strikingly, the altermagnetic spin splitting within BiFeO3 skyrmion can be reversed through the application of an electric field, revealed via the Circular photogalvanic effect. This quasiparticle, which possesses a neutral topological charge, holds substantial promise for diverse applications-most notably, enabling the development of unconventional computing systems with low power consumption and magnetoelectric controllability.