Spin-Torque Generation in Topological-Insulator-Based Heterostructures

Abstract

Heterostructures utilizing topological insulators exhibit a remarkable spin-torque efficiency. However, the exact origin of the strong torque, in particular whether it stems from the spin-momentum locking of the topological surface states or rather from spin-Hall physics of the topological-insulator bulk remains unclear. Here, we explore a mechanism of spin-torque generation purely based on the topological surface states. We consider topological-insulator-based bilayers involving ferromagnetic metal (TI/FM) and magnetically doped topological insulators (TI/mdTI), respectively. By ascribing the key theoretical differences between the two setups to location and number of active surface states, we describe both setups within the same framework of spin diffusion of the non-equilibrium spin density of the topological surface states. For the TI/FM bilayer, we find large spin-torque efficiencies of roughly equal magnitude for both in-plane and out-of-plane spin torques. For the TI/mdTI bilayer, we elucidate the dominance of the spin-transfer-like torque. However, we cannot explain the orders of magnitude enhancement reported. Nevertheless, our model gives an intuitive picture of spin-torque generation in topological-insulator-based bilayers and provides theoretical constraints on spin-torque generation due to topological surface states.

updated version including a discussion of TI/FM as well as TI/ magnetically doped TI heterostructures

References in corpus (6)

• Spin Transfer Torque Generated by the Topological Insulator Bi_2Se_3
• Spin-Charge Locking and Tunneling into a Helical Metal
• Spin and Orbital Magnetic Response on the Surface of a Topological Insulator
• Spin diffusion and magnetoresistance in ferromagnet/topological-insulator junctions
• Minimal Model of Spin-Transfer Torque and Spin Pumping caused by Spin Hall Effect
• Effects of surface-bulk hybridization in 3D topological `metals'

Cited by in corpus (35)

• Current-induced spin-orbit torques in ferromagnetic and antiferromagnetic systems
• Room-temperature perpendicular magnetization switching through giant spin-orbit torque from sputtered BixSe(1-x) topological insulator material
• Fermi level dependent charge-to-spin current conversion by Dirac surface state of topological insulators
• Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques
• Transport in two-dimensional topological materials: recent developments in experiment and theory
• Dirac Spin-Orbit Torques at the Surface of Topological Insulators
• Strongly exchange-coupled and surface-state-modulated magnetization dynamics in Bi2Se3/YIG heterostructures
• Band structure and spin texture of Bi${}_2$Se${}_3$/3d ferromagnetic metal interface
• Spin-orbit torque in 3D topological insulator-ferromagnet heterostructure: crossover between bulk and surface transport
• Control of spin-orbit torques by interface engineering in topological insulator heterostructures
• Giant Edelstein effect in Topological-Insulator--Graphene heterostructures
• Benchmarking of spin-orbit torque switching efficiency in Pt alloys
• Spin Orbit Torque in two dimensional Antiferromagnetic Topological Insulators
• Hybridization-induced interface states in a topological insulator-magnetic metal heterostructure
• Van der Waals heterostructures with spin-orbit coupling
• Highly Tunable Spin-Orbit Torque and Anisotropic Magnetoresistance in a Topological Insulator Thin Film Attached to Ferromagnetic Layer
• Skyrmion-induced bound states on the surface of 3D Topological Insulators
• Spin-Hall effect due to the bulk states of topological insulators: Extrinsic contribution to the conserved spin current
• Semi-realistic tight-binding model for spin-orbit torques
• Spin transfer torques due to the bulk states of topological insulators
• Voltage-driven Magnetization Switching via Dirac Magnetic Anisotropy and Spin--orbit Torque in Topological-insulator-based Magnetic Heterostructures
• Fulde-Ferrell States in Inverse Proximity Coupled Magnetically-Doped Topological Heterostructures
• Observation of the topological Dirac fermions and surface states in superconducting BaSn3
• Spin torque and persistent currents caused by percolation of topological surface states
• High-performance nanoscale topological energy transduction
• Persistent currents and spin torque caused by percolated quantum spin Hall state
• Low power In Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures
• Current-induced switching of magnetic molecules on topological insulator surfaces
• Spin-Hall effect in topological materials: Evaluating the proper spin current in systems with arbitrary degeneracies
• Tunable spin-charge conversion through topological phase transitions in zigzag nanoribbons
• Spin-torque resonance due to diffusive dynamics at a surface of topological insulator
• Strong Spin-Orbit Torque effect on magnetic defects due to topological surface state electrons in Bi${}_2$Te${}_3$
• Proximity-induced zero-energy states indistinguishable from topological edge states
• Spin accumulation in disordered topological insulator thin films
• Determination of Out-of-plane Spin Polarization of Topological Surface States by Spin Hall Effect Tunneling Spectroscopy