Fermi Level Dependent Spin Pumping from a Magnetic Insulator into a Topological Insulator

Abstract

Topological spintronics aims to exploit the spin-momentum locking in the helical surface states of topological insulators for spin-orbit torque devices. We address a fundamental question that still remains unresolved in this context: does the topological surface state alone produce the largest values of spin-charge conversion efficiency or can the strongly spin-orbit coupled bulk states also contribute significantly? By studying the Fermi level dependence of spin pumping in topological insulator/ferrimagnetic insulator bilayers, we show that the spin Hall conductivity is constant when the Fermi level is tuned across the bulk band gap, consistent with a full bulk band calculation. The results suggest a new perspective, wherein "bulk-surface correspondence" allows spin-charge conversion to be simultaneously viewed either as coming from the full bulk band, or from spin-momentum locking of the surface state.

References in corpus (21)

• Topological Insulators
• Spin Transfer Torque Generated by the Topological Insulator Bi_2Se_3
• Nonlocal magnetization dynamics in ferromagnetic heterostructures
• Scaling of spin Hall angle in 3d, 4d and 5d metals from Y3Fe5O12/metal spin pumping
• Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers
• Room-temperature perpendicular magnetization switching through giant spin-orbit torque from sputtered BixSe(1-x) topological insulator material
• A conductive topological insulator with colossal spin Hall effect for ultra-low power spin-orbit-torque switching
• Room temperature spin-orbit torque switching induced by a topological insulator
• Fermi level dependent charge-to-spin current conversion by Dirac surface state of topological insulators
• Spin-pumping into surface states of topological insulator α-Sn, spin to charge conversion at room temperature
• Room temperature magnetization switching in topological insulator-ferromagnet heterostructures by spin-orbit torques
• Acoustic spin pumping as the origin of the long-range spin Seebeck effect
• Surface state dominated spin-charge current conversion in topological insulator/ferromagnetic insulator heterostructures
• Observation of inverse spin Hall effect in bismuth selenide
• Independent tuning of electronic properties and induced ferromagnetism in topological insulators with heterostructure approach
• Spin-Polarized Tunneling Study on Spin-Momentum Locking in the Topological Insulators
• Enhanced spin Seebeck effect signal due to spin-momentum locked topological surface states
• Mapping the chemical potential dependence of current-induced spin polarization in a topological insulator
• Probing the Spin Pumping Mechanism: Exchange Coupling with Exponential Decay in Y3Fe5O12/barrier/Pt Heterostructures
• Band structure and spin texture of Bi${}_2$Se${}_3$/3d ferromagnetic metal interface
• Tunable Giant Spin Hall Conductivities in a Strong Spin-Orbit Semimetal: Bi${}_{1-x}$Sb${}_x$

Cited by in corpus (15)

• Electrical control of magnetism by electric field and current-induced torques
• Changes of Magnetism in a Magnetic Insulator due to Proximity to a Topological Insulator
• Spin and charge interconversion in Dirac semimetal thin films
• Large unidirectional spin Hall and Rashba-Edelstein magnetoresistance in topological insulator/magnetic insulator heterostructures
• Light and microwave driven spin pumping across FeGaB-BiSb interface
• Non-Contact Spin Pumping by Microwave Evanescent Fields
• All-electrical Magnon Transport Experiments in Magnetically Ordered Insulators
• Giant spin torque efficiency in naturally oxidized polycrystalline TaAs thin films
• Opposite current-induced spin polarizations in bulk-metallic Bi2Se3 and bulk-insulating Bi2Te2Se topological insulator thin flakes
• Effects of Crystalline Disorder on Interfacial and Magnetic Properties of Sputtered Topological Insulator/Ferromagnet Heterostructures
• Voltage-control of damping constant in magnetic-insulator/topological-insulator bilayers
• Spin Hall conductivity in Bi${}_{1-x}$Sb${}_x$ as an experimental test of bulk-boundary correspondence
• Gate-Tunable Spin-to-Charge Conversion in Topological Insulator-Magnetic Insulator Heterostructures at Room Temperature
• Materials Relevant to Realizing a Field-Effect Transistor based on Spin-Orbit Torques
• Tracing Dirac points of topological surface states by ferromagnetic resonance