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MA: Fachverband Magnetismus

MA 29: Spin-Dependent Phenomena in 2 D

MA 29.10: Vortrag

Mittwoch, 20. März 2024, 17:30–17:45, EB 202

Half-metallic transport and spin-polarized tunneling through the 2D ferromagnet Fe₄GeTe₂ — •Anita Halder^1,2, Declan Nell¹, Antik Sihi¹, Stefano Sanvito¹, and Andrea Droghetti^1,3 — ¹Trinity College Dublin, Dublin, Ireland — ²SRM University-AP, Amravati, India — ³CNR-SPIN, at G. d′Annunzio University, Chieti, Italy

The discovery of ferromagnetic 2D van der Waals (vdW) materials, Fe_nGeTe₂ (FGT) (n=3-5), has attracted attention for spintronics applications due to their high Curie temperature. We theoretically study the spin-dependent transport properties of Fe₄GeTe₂ (FGT4) using density functional theory and Non-equilibrium Green’s Functions. We show that the conductance perpendicular to the 2D vdW layer is half-metallic, i.e. entirely spin-polarized (SP). This high SP remains robust transitioning from bulk to a single layer. Additionally, a large SP current is observed when the system is driven out of equilibrium up to a significant bias. This spin-dependent transport is largely unaffected in the presence of spin-orbit coupling and electron-electron correlation effects. Leveraging the spin-filtering capability of monolayer FGT4 presents an opportunity for designing a magnetic tunnel junction (MTJ) using 2D vdW materials, offering high tunnel magnetoresistance (TMR). An MTJ device exploiting the vdW gap as an insulating barrier between two FGT4 layers achieves a TMR of almost 500%. These findings may inspire further theoretical and experimental studies for designing more realistic spintronic devices, replacing conventional FM with 2D vdW materials.

Keywords: van der Waals materials; Magntic tunnel junction; spin-dependent transport; Spin polarization; Tunnel magnetoresistance