Intrinsic spin Hall torque in a moire Chern magnet

Abstract

In spin torque magnetic memories, electrically actuated spin currents are used to switch a magnetic bit. Typically, these require a multilayer geometry including both a free ferromagnetic layer and a second layer providing spin injection. For example, spin may be injected by a nonmagnetic layer exhibiting a large spin Hall effect, a phenomenon known as spin-orbit torque. Here, we demonstrate a spin-orbit torque magnetic bit in a single two-dimensional system with intrinsic magnetism and strong Berry curvature. We study AB-stacked MoTe2/WSe2, which hosts a magnetic Chern insulator at a carrier density of one hole per moire superlattice site. We observe hysteretic switching of the resistivity as a function of applied current. Magnetic imaging using a superconducting quantum interference device reveals that current switches correspond to reversals of individual magnetic domains. The real space pattern of domain reversals aligns precisely with spin accumulation measured near the high-Berry curvature Hubbard band edges. This suggests that intrinsic spin- or valley-Hall torques drive the observed current-driven magnetic switching in both MoTe2/WSe2 and other moire materials. The switching current density of 10^3 Amps per square centimeter is significantly less than reported in other platforms paving the way for efficient control of magnetic order.

References in corpus (8)

• Nonlocal edge state transport in the quantum spin Hall state
• Probing magnetism in 2D materials at the nanoscale with single spin microscopy
• SQUID-on-tip with single-electron spin sensitivity for high-field and ultra-low temperature nanomagnetic imaging
• Current Switching of Valley Polarization in Twisted Bilayer Graphene
• Realization of the Haldane Chern insulator in a moiré lattice
• Quantum anomalous Hall effect and electric-field-induced topological phase transition in AB-stacked MoTe${}_2$/WSe${}_2$ moiré heterobilayers
• Valley-coherent quantum anomalous Hall state in AB-stacked MoTe2/WSe2 bilayers
• Spin-textured Chern bands in AB-stacked transition metal dichalcogenide bilayers

Cited by in corpus (15)

• A Microscopic Perspective on Moiré Materials
• Mapping twist-tuned multiband topology in bilayer WSe${}_2$
• Tunable moiré materials for probing Berry physics and topology
• Twist-angle tunable spin texture in WSe${}_2$/graphene van der Waals heterostructures
• Superconductivity and spin canting in spin-orbit proximitized rhombohedral trilayer graphene
• Scanning SQUID-on-tip microscope in a top-loading cryogen-free dilution refrigerator
• Observation of first-order quantum phase transitions and ferromagnetism in twisted double bilayer graphene
• Optical Switching of Moiré Chern Ferromagnet
• Topological $p_x+i{p}_y$ inter-valley coherent state in Moiré MoTe${}_2$/WSe${}_2$ heterobilayers
• Unconventional Metallic Magnetism: Non-analyticity and Sign-changing Behavior of Orbital Magnetization in ABC Trilayer Graphene
• Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides
• Magnetic Moiré Systems: a review
• Signatures of electronic ordering in transport in graphene flat bands
• Cryogenic spin Peltier effect detected by a RuO${}_2$-AlO${}_x$ on-chip microthermometer
• Designing Magnetic Topological Insulator Trilayers for Highly-Efficient Spin-Orbit Torque Switching