2DSPIN-TECH investigated 2D materials for spintronic memory devices, from synthesis to applications in non-volatile memory. The project began with the growth of spin-orbit materials (2DSOMs) and 2D ferromagnets (2DFMs). 2D semiconductors, such as Janus transition metal dichalcogenides, were grown, which exhibit asymmetric crystal structures, and are expected to provide out-of-plane current-induced spin polarization. On the other hand, Weyl semimetals exhibit large out-of-plane spin polarization from strong spin-orbit coupling and broken symmetry, showing promises for memory devices.
2DFMs, such as cobalt- and nickel-doped Fe₅GeTe2 and Fe₃GaTe2 were grown, showing stable magnetic properties above room temperature, addressing a key challenge in 2D magnetism. Doping tunes Curie temperature and magnetic anisotropy and some compositions show coexistence of ferromagnetic and antiferromagnetic orders above room temperature, creating intrinsic exchange bias and canted perpendicular magnetism. This non-trivial magnetic order enables energy-efficient, magnetic field-free, deterministic spin-orbit torque (SOT) switching.
Stacked in van der Waals heterostructures, these layered materials allow customizable interfaces. Theoretical studies show how twisting layers affect spin-orbit and magnetic proximity interactions. Devices from such stacks reveal spin-orbit effects, such as Rashba and Ising splitting, which enable control spin orientation electrically.
Finally, we built foundational spin-orbit torque memory devices, demonstrating energy-efficient magnetization switching. Combining TaIrTe₄ and Fe₃GaTe2 heterostructures enabled deterministic magnetization switching at room temperature using simple electrical pulse current, without the need for external magnets, thereby advancing efficient memory technology.
Overall, 2DSPIN-TECH established a foundation for energy-efficient, all-electric memory devices based on van der Waals heterostructures. Breakthroughs in material synthesis, interface control, out-of-plane spin polarization, and magnetization switching reveal new electronic functionalities. Next steps include optimizing device performance and parameters at the atomic level, supported by advanced simulations to better understand ferromagnets and spin-orbit torques, thereby guiding the design of next-generation spintronic devices.
