Robust High Mobility Half-Metallic Interface State in CrI<sub>3</sub>/WTe<sub>2</sub> Based Heterostructures.

Abstract

We report a robust half-metallic interface state in the CrI₃/2H-WTe₂ van der Waals (vdW) heterostructure, exhibiting 100% spin polarization and an extraordinary magnetoresistance exceeding 1 × 10⁹%. These unique properties position the CrI₃/2H-WTe₂ configuration as an exceptional candidate for applications in data storage, spintronics, and spin caloritronics. By designing a device incorporating CrO₂ electrodes, we model charge and spin transport in this heterostructure and analyze the thermal properties under parallel (PM) and antiparallel (APM) magnetization states. Using density functional theory (DFT) and nonequilibrium Green's function (NEGF) methods, we explore how variations in temperature between CrO₂ electrodes impact spin-polarized currents and demonstrate nearly perfect spin filtration efficiency at low temperatures across both the 1<i>T</i>' and 2H phases of WTe₂. The device also shows high thermal magnetoresistance (MR), further enhancing its applicability for spin-caloritronic functions. Transmission spectra for PM and APM states reveal temperature-dependent spin transport, reinforcing the heterostructure's spin filtering effectiveness. This study represents the first detailed investigation of a heterostructure device with CrI₃ and WTe₂ phases and CrO₂ electrodes, highlighting the superior spin filtration and MR capabilities of the CrI₃/2H-WTe₂ interface. The robust half-metallic state and remarkable spin filtering efficiency underscore the potential of this structure for developing advanced thermally controlled spintronic and spin-caloritronic devices.