Electrical Manipulation of Spin Splitting Torque in Altermagnetic RuO2

TL;DR

This paper demonstrates electrical control of spin splitting torque in altermagnetic RuO2 by switching the Ne9el vector, enabling potential applications in high-speed spintronic devices with enhanced controllability.

Contribution

It provides the first experimental demonstration of electrical manipulation of Ne9el vector and spin splitting torque in altermagnets, confirmed by XMLD and transport measurements.

Findings

Electrical switching of Ne9el vector via spin-orbit torque.

Reversible polarity observed in transport measurements.

XMLD confirms the existence of Ne9el vector in altermagnets.

Abstract

Due to nonrelativistic altermagnetic spin splitting effect (ASSE), altermagnets can generate time-reversal-odd spin current and spin splitting torque (SST) with spin polarization parallel to the N\'eel vector. Hence the effective manipulation of SST would provide plenty of opportunities for designable spintronic devices, which remains elusive. Here, the electrical control of SST is achieved in altermagnetic RuO2, based on controllable N\'eel vector of RuO2 and N\'eel vector-dependent generation of SST. We demonstrate the current-induced switching of N\'eel vector via spin-orbit torque in RuO2 films, according to the reversible polarity of electrical transport measurements and X-ray magnetic linear dichroism (XMLD). The XMLD also unprecedentedly demonstrates that N\'eel vector really exists in altermagnets. The switching of N\'eel vector to the current direction and resultantly enhanced spin polarization parallel to the N\'eel vector brings about stronger ASSE-induced spin current. Our findings not only enrich the properties of altermagnets but also pave the way for high speed memories and nano-oscillators with excellent controllability and efficiency.