2D Magnetic and Topological Quantum Materials and Devices for Ultralow Power Spintronics

ABSTRACT 2D magnetic and topological quantum materials (TQMs) offer a novel way of ultralow‐power spintronic memory and logic devices by combining symmetrically protected transport with tunable magnetic order. This review focuses on the key fundamentals of 2D magnetism by explaining how Ising/XY/Heisenberg spin symmetries and magnetic anisotropy stabilize and govern long‐range magnetic order. We then describe how spin–orbit coupling (SOC) alters the electronic band structure, including SOC‐driven band inversion. We also discuss how the combination of band topology and magnetic symmetry breaking gives rise to topological phases and spin transport. Further, it discusses different synthesis routes from exfoliated flakes to wafer scale Molecular Beam Epitaxy (MBE)/Chemical Vapour Deposition (CVD) and van der Waals stacking of multiple 2D layers, heterostructure device engineering can help in tuning Curie/Néel temperatures, interfacial exchange, and band topology. We survey device platforms where these materials translate symmetry and Berry curvature into performance, such as highly efficient spin orbit torque (SOT) memories including field‐free switching in low symmetry semimetals and topological/ferromagnetic stacks. In addition, this review talks about all 2D heterostructures using vdW magnets, tunneling devices, and spin‐filter magnetic tunnel junction (MTJ) with atomically sharp barriers, and magnetoresistive/readout schemes leveraging unidirectional spin Hall magnetoresistance (USMR/UMR) and nonlinear Hall responses. We further examine magnetic topological insulators quantum anomalous/spin hall devices that enable dissipationless edge‐state readout and gate‐reconfigurable functionality.