Fig. 1: Crystal structure and schematic of the altermagnetic RuO2.
From: Magnetic memory driven by spin splitting torque in nonrelativistic collinear antiferromagnet
a The crystal structure of RuO2 with spin orientations indicated (green and blue arrows) with (001)-RuO2 plane and the coordinate system defined by the a[100], b[010] and c[001] axes (red arrows) (Left). The purple spheres represent the Ru atoms. The (101) crystal plane highlighted in orange, with its coordinates by the x[10\(\bar{1}\)], y[010] and z[101] axis (black arrows) (Right). The applied E is along the axis with b[010]. Right: The front view from the crystal structure with (001)-RuO2 (Left). θ is the angle of the N to the z[101] axis. When E (yellow arrow) is away from the axis with ϕ = 45° in (b) the charge current (Jc, purple arrow) is along kx (or ky) axis and leads to the flow of transverse spin-polarized current (Js, red arrow) induced by SST in (c). ϕ is the angle of the electric field relative to the kx axis. d Real space for (101)-oriented RuO2-pMTJ transversal spin current flowing along the out-of-plane induced by the charge current along the [010] axis. e x-ray diffraction 2θ/ω scan for 12 nm RuO2 film. Inset: rocking curve of (101)-RuO2. f High-resolution HAADF image of the cross-section of Al2O3//RuO2 thin film. g Schematic of XMLD measurement geometry. XAS spectra with ϕ = 0° and 90° of Ru4+ M3 and M2 edges in (h) Al2O3(1\(\bar{1}\)02)//RuO2(101). i The XMLD intensity of Ru4+ M3 for (101)-, (110)- and (001)-RuO2 samples at room temperature.
