ABSTARCT:

Reducing the energy consumption is one of the major challenges for next-generation spintronic devices. Spin-momentum locking in topological surface states gives rise to a giant spin-orbit torque (SOT) efficiency, and thus to reduce the writing energy of SOT devices. Here, by combing the topological insulators (TIs) with in-plane magnetic tunnel junctions (MTJs), we demonstrate the proof-of-concept SOT-MRAM cell, where a large TMR ratio of 102% and the ultralow switching current density of 1.2 × 105 A cm−2 have been simultaneously achieved at room temperature. Next, by combing the TIs with perpendicular MTJs, we realize the all-electrical low-power writing operation by combing the SOT with a small spin-transfer torque current, with the improving thermal stability and storage density. Finally, I will show our recent progress based on the novel spin-splitting torque (SST) from alermagentic RuO2, and demonstrate the altermagentic SST-MRAM devices with field-free and energy-efficient writing process. Our work proposes and demonstrates the magnetic memory driven by topological insulators and altermagnets, which may inspire the revolution of spintronic devices from classical to quantum materials.

BIOGRAPHY:

Prof. Hao Wu graduated from Lanzhou University in 2012 and obtained his PhD degree from the Institute of Physics, Chinese Academy of Sciences in 2017, and then worked as a postdoctoral researcher at the University of California, Los Angeles (UCLA) during 2017 ~ 2021. Since 2021, Dr. Hao Wu has been working at the Songshan Lake Materials Laboratory, and was the head of the Spintronic Quantum Materials and Devices group. He was a recipient of the National Overseas High-Level Young Talents Program. He has published more than 100 papers in peer-reviewed journals such as Nature Electronics/Communications, Physical Review Letters, Advanced Materials, etc., with more than 3800 citations. He has presented at over 10 international academic conferences. He has been honored with the Young Scientist Medal by the International Association of Advanced Materials.