Electrically Controlled Spin Injection from Giant Rashba Spin–Orbit Conductor BiTeBr

Abstract

Ferromagnetic materials are the widely used source of spin-polarized electrons in spintronic devices, which are controlled by external magnetic fields or spin-transfer torque methods. However, with increasing demand for smaller and faster spintronic components, utilization of spin-orbit phenomena provides promising alternatives. New materials with unique spin textures are highly desirable since all-electric creation and control of spin polarization is expected, where the strength, as well as an arbitrary orientation of the polarization, can be defined without the use of a magnetic field. In this work, we use a novel spin-orbit crystal BiTeBr for this purpose. Owning to its giant Rashba spin splitting, bulk spin polarization is created at room temperature by an electric current. Integrating BiTeBr crystal into graphene-based spin valve devices, we demonstrate for the first time that it acts as a current-controlled spin injector, opening new avenues for future spintronic applications in integrated circuits.

Gate-tunable spin-galvanic effect in graphene-topological insulator van der Waals heterostructures at room temperature

“…The key to these technologies so far is the use of heavy metals, semiconductors, and heterostructure interfaces of metals and oxides, which allow for spin-charge interconversion due to their strong spin–orbit interaction (SOI) and broken inversion symmetry 7 . Recently, such spin-charge conversion process and its inverse phenomenon were investigated in Weyl semimetals 8 , 9 , Rashba materials 10 , transition metal dichalcogenides (TMDs) 11 , and graphene/TMD heterostructures 12 – 14 .…”

Strain-enhanced giant Rashba spin splitting in ultrathin KTaO3 films for spin-polarized photocurrents

“…10 In addition, it is very interesting to manipulate the Rashba spin-orbit coupling by applying stress, as were done in 2D LaOBiS 2 , 11 binary alloyed hexagonal nanosheets, 12 2D heterostructures, 13 BiSb monolayer, 14 and BiTeI monolayer. 15 Large Rashba interaction can be used to realize spin polarization and spin injection by applying electric eld 16,17 and produce spinpolarized photocurrents through polarized light. [18][19][20][21][22][23] Recently, a 2DEG was observed at KTaO 3 (KTO) (100) surface 24,25 in terms of the angle-resolved photoemission (ARPES) spectrum.…”

All-electrical creation and control of spin-galvanic signal in graphene and molybdenum ditelluride heterostructures at room temperature

“…Specifically, the SOI is the origin of fascinating effects like current-induced transverse spin polarization in non-magnetic materials, known as spin Hall effect (SHE) in bulk, Rashba-Edelstein effect (REE) at the heterostructure interfaces, and spin-momentum locking (SML) in topological materials 5 . Recent experiments utilizing the charge-to-spin conversion (CSC) and its inverse effects have been performed on metallic multilayers 6 , semiconductors 2 , oxide heterostructures 7,8 , two-dimensional (2D) materials 9,10 , van der Waals (vdW) heterostructures with graphene (Gr) [11][12][13][14][15][16][17] , and the topological insulators 18,19 . Such SOI-induced charge-spin conversion features are promising for all-electrical spinorbit torque-based technology [1][2][3][4] .…”