Heterogeneous Integration of Single‐Crystal SrRuO₃ Films with Large Spin Hall Conductivity on Silicon for Spintronic Devices

Abstract Spin‐orbit torque (SOT) device has been recognized as a promising candidate for next‐generation information devices, owing to its energy‐efficient, high‐speed and scalable potential. Complex oxides show large spin Hall conductivity ( σ SH ), thus are capable of inducing efficient SOT. However, corresponding SOT device integrated on silicon has rarely been reported due to the technical challenges in film preparation. Here, a hybrid transfer and epitaxy strategy for integrating single‐crystalline SrRuO 3 on silicon buffered with transferred freestanding SrTiO 3 membrane is demonstrated. The integrated SrRuO 3 exhibits a large σ SH of 6.1 × 10 4 ħ/2e S m −1 , enabling magnetization switching in a CoPt layer with an ultra‐low critical current density of 1.3 × 10 10 A m −2 , being lower than heavy metals by 1–2 orders of magnitude. What's more, this SOT‐induced switching displays multiple intermediate magnetization states, which is able to mimic synapse and neuron behavior. Simulating a two‐layer artificial neural network using experimentally extracted device parameters achieve an accuracy of 88% for image recognition. The results showcase the successful integration of single‐crystalline oxides on silicon, paving the way for high‐performance, silicon‐compatible spintronic devices.