2025/12/24 by Dongchao Yang, Zhaoqing Li, Yang, Dongchao +11
Materials Science · Physics and Astronomy · #Chemical and Physical Properties of Materials #FOS: Physical sciences #Magnetic properties of thin films #Materials Science (cond-mat.mtrl-sci) #Topological Materials and Phenomena
paper · doi:10.48550/arxiv.2512.21100
openalex publication_date 2025/12/24 · openalex created_date 2025/12/26 · openalex updated_date 2026/07/28
Spin-orbit torque efficiency is conventionally fixed by bulk materials. D-wave altermagnets introduce an additional nonrelativistic spin-charge conversion channel beyond inverse spin-Hall effect. Using prototypical candidate RuO2 as an example, we show that the adjacent ferromagnet alone can dictate both the magnitude and sign of spin-charge conversion. Spin-pumping measurements on RuO2/Y3Fe5O12 (YIG) and RuO2/Ni80Fe20 (Py) bilayers yield opposite effective spin-Hall angles that persist across crystalline and polycrystalline RuO2. Inserting an ultrathin Au spacer at the RuO2/YIG interface reverses the signal, envidencing a dominant interfacial inverse Rashba-Edelstein effect, whereas RuO2/Py is governed by bulk inverse spin-Hall effect. First-principles calculations trace this dichotomy to interface-selective band hybridization: Rashba surface states survive at the insulating YIG contact yet are quenched by metallic Py. Our findings establish ferromagnetic interfacing as a deterministic knob for tailoring spin-charge conversion in altermagnetic oxides, paving the way to field-free, low-dissipation spintronic memory devices.