Designing Magnetic Topological Insulator Trilayers for Highly-Efficient Spin-Orbit Torque Switching

Abstract

Spin-orbit torque (SOT) enables efficient electrical control of magnetization, offering a pathway towards low-power spintronic devices. Magnetic topological insulators (TIs), with spin-momentum-locked surface states and intrinsic ferromagnetism, provide a unique platform for realizing SOT switching of edge current chirality in quantum anomalous Hall (QAH) insulators. In this work, we employ molecular beam epitaxy to synthesize a series of magnetic TI trilayers with controlled layer thicknesses on heat-treated SrTiO3(111) substrates. Electrical transport measurements reveal that SOT-driven magnetization reversal and the associated switching of edge current chirality are governed by the SrTiO3(111) substrate-induced charging effect, which generates an asymmetric chemical-potential alignment between the top and bottom magnetic TI layers. Furthermore, we demonstrate that the switching polarity and efficiency can be tuned through heterostructure design, gate voltage, and in-plane magnetic field, consistent with SOT symmetry. These findings identify chemical potential asymmetry as the origin of the large SOT switching ratio in magnetic TI trilayers and establish a route for electrical control of edge current chirality in QAH insulators. This work advances the understanding of SOT switching mechanism in magnetic topological materials and paves the way for next-generation, energy-efficient QAH-based logic and memory devices.

20 pages and 4 figures. Comments are very welcome

References in corpus (30)

• Topological Insulators
• Topological insulators and superconductors
• Spin torque switching with the giant spin Hall effect of tantalum
• Experimental Observation of the Quantum Anomalous Hall Effect in a Magnetic Topological Insulator
• Magnetic switching by spin torque from the spin Hall effect
• Spin Torque Ferromagnetic Resonance Induced by the Spin Hall Effect
• Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems
• Spin Transfer Torque Generated by the Topological Insulator Bi_2Se_3
• Intrinsic quantized anomalous Hall effect in a moiré heterostructure
• High-precision realization of robust quantum anomalous Hall state in a hard ferromagnetic topological insulator
• Control of spin-orbit torques through crystal symmetry in WTe2/ferromagnet bilayers
• Trajectory of Anomalous Hall Effect toward the Quantized State in a Ferromagnetic Topological Insulator
• Gate-Voltage Control of Chemical Potential and Weak Anti-localization in Bismuth Selenide
• Scale-Invariant Dissipationless Chiral Transport in Magnetic Topological Insulators beyond the Two-Dimensional Limit
• Roadmap of spin-orbit torques
• Colloquium: Quantum anomalous Hall effect
• Room temperature spin-orbit torque switching induced by a topological insulator
• Magnetic modulation doping in topological insulators toward higher-temperature quantum anomalous Hall effect
• Carrier-independent ferromagnetism and giant anomalous Hall effect in magnetic topological insulator
• Tuning Chern Number in Quantum Anomalous Hall Insulators
• Current-nonlinear Hall effect and spin-orbit torque magnetization switching in a magnetic topological insulator
• Concurrence of Quantum Anomalous Hall and Topological Hall Effects in Magnetic Topological Insulator Sandwich Heterostructures
• Observation of the quantum-anomalous-Hall insulator to Anderson insulator quantum phase transition and its scaling behavior
• Quantum Hall States Stabilized in Semi-magnetic Bilayers of Topological Insulators
• Confinement-Induced Chiral Edge Channel Interaction in Quantum Anomalous Hall Insulators
• Intrinsic spin Hall torque in a moire Chern magnet
• Zero Magnetic Field Plateau Phase Transition in Higher Chern Number Quantum Anomalous Hall Insulators
• Electrical Switching of the Edge Current Chirality in Quantum Anomalous Hall Insulators
• Giant Hall Switching by Surface-State-Mediated Spin-Orbit Torque in a Hard Ferromagnetic Topological Insulator
• Interlayer Coupling-Induced Quantum Phase Transition in Quantum Anomalous Hall Multilayers