High tunnel magnetoresistance based on 2D Dirac spin gapless semiconductor VCI_3

摘要

Future spintronic devices on the nanoscale require low-dimensional materials with high spin polarization. Transition-metal trichlorides have received much attention because 2D ferromagnetism is observed in them such as the ferromagnetic semiconductor of CrI3 monolayer and the ferromagnetic Dirac spin gapless semiconductor of VCl3 monolayer with 100% spin polarization. What about their spin transport properties? Here, we design the magnetic tunnel junction of VCl3/CoBr3/VCl3 with the electrode of the spin gapless semiconductor of VCl3 monolayer and the tunneling barrier of the nonmagnetic semiconductor of CoBr3 monolayer and explore the spin-polarized bias-voltage-dependent tunneling current. Our first-principles calculations combined with nonequilibrium Green's function indicate that VCl3/CoBr3/VCl3 exhibits a high tunnel magnetoresistance ratio (up to 4.5 x 10(12)%) and a perfect spin filtering effect, which make the VCl3 monolayer useful in 2D spintronic devices. The physical origins of these versatile spin transport properties are discussed in terms of the spin gapless semiconductor property of the VCl3 monolayer and the spin-dependent transmission spectrum.