Electrical manipulation of spin splitting torque in altermagnetic RuO2.

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 Néel vector. Hence the effective manipulation of SST would provide plenty of opportunities for designable spintronic devices. Here, we achieve electrical control of SST in altermagnetic RuO2, based on controllable Néel vector of RuO2 and Néel vector-dependent generation of SST. To demonstrate the current-induced switching of Néel vector via spin-orbit torque in RuO2 films, we use electrical transport measurements and X-ray magnetic linear dichroism (XMLD) measurements. The switching of Néel vector to the current direction and resultantly enhanced spin polarization parallel to the Néel vector brings about stronger ASSE-induced spin current. These findings not only enrich our understanding of the properties of altermagnets but also pave the way for high-speed memories and nano-oscillators with excellent controllability and efficiency.