Low-Power and Field-Free Perpendicular Magnetic Memory Driven by Topological Insulators.

Giant spin-orbit torque (SOT) from topological insulators (TIs) has great potential for low-power SOT-driven magnetic random-access memory (SOT-MRAM). In this work, a functional 3-terminal SOT-MRAM device is demonstrated by integrating the TI [(BiSb)(2)Te-3] with perpendicular magnetic tunnel junctions (pMTJs), where the tunneling magnetoresistance is employed for the effective reading method. An ultralow switching current density of 1.5 x 10(5) A cm(-2) is achieved in the TI-pMTJ device at room temperature, which is 1-2 orders of magnitude lower than that in conventional heavy-metals-based systems, due to the high SOT efficiency & theta;(SH) = 1.16 of (BiSb)(2)Te-3. Furthermore, all-electrical field-free writing is realized by the synergistic effect of a small spin-transfer torque current during the SOT. The thermal stability factor (& UDelta; = 66) shows the high retention time (>10 years) of the TI-pMTJ device. This work sheds light to the future low-power, high-density, and high-endurance/retention magnetic memory technology based on quantum materials.