Field-Free Rashba-Type Crystal Torque MRAM with High Efficiency and Thermal Stability

We report a field-free switching (FFS) scheme of Rashba-type crystal torque magnetic random-access memory (CT-MRAM) based on the AIInSb/InSb/CdTe heterostructures. Benefiting from the giant interfacial Rashba spin-orbit coupling (SOC), the spin-orbit torque efficiency of the spin-generation channel $(\xi=1.5)$ is four times larger than the conventional heavy-metal systems, enabling an ultra-low write current density of $J_{\mathrm{S}\mathrm{W}}=7.5\times 10^{5}\mathrm{A}/\text{cm}^{2}$ at room temperature. Moreover, the crystal torque inherited from the low-symmetry point group $(3m1)$ not only simplifies the device structure, but also warrants a stable FFS operation over a wide temperature range from $-40^{\circ}\mathrm{C}$ to $12 5^{\circ}\mathrm{C}$.