Tunneling magnetoresistance devices based on topological insulators: Ferromagnet/insulator/topological-insulator junctions employing Bi${}_2$Se${}_3$

Abstract

We theoretically investigate tunneling magnetoresistance (TMR) devices, which are probing the spin-momentum coupled nature of surface states of the three-dimensional topological insulator Bi${}_2$Se${}_3$. Theoretical calculations are performed based on a realistic tight-binding model for Bi${}_2$Se${}_3$. We study both three dimensional devices, which exploit the surface states of Bi${}_2$Se${}_3$, as well as two-dimensional devices, which exploit the edge states of thin Bi${}_2$Se${}_3$ strips. We demonstrate that the material properties of Bi${}_2$Se${}_3$ allow a TMR ratio at room temperature of the order of 1000%. Analytical formulas are derived that allow a quick estimate of the achievable TMR ratio in these devices. The devices can be used to measure the spin polarization of the topological surface states as an alternative to spin-ARPES. Unlike TMR devices based on magnetic tunnel junctions the present devices avoid the use of a second ferromagnetic electrode whose magnetization needs to be pinned.

11 pages, 10 figures, improved manuscript including a new device proposal and more detailed discussions

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Cited by in corpus (5)

• Topological properties of multi-terminal superconducting nanostructures: effect of a continuous spectrum
• Confinement and Fermion Doubling Problem in Dirac-like Hamiltonians
• Topological flat bands in optical checkerboard-like lattices
• Low power In Memory Computation with Reciprocal Ferromagnet/Topological Insulator Heterostructures
• Determination of Out-of-plane Spin Polarization of Topological Surface States by Spin Hall Effect Tunneling Spectroscopy