Spin filters based on two-dimensional materials Co₂Si and Cu₂Si

Spintronic devices have several advantages compared with conventional electronic devices, including non-volatility, faster data processing speed, higher integration densities, less electric power consumption and so on. However, we still face challenges for efficiently generating and injecting pure spin polarized current. In this work, we utilize two kinds of two-dimensional materials Co₂Si and Cu₂Si with both lattice match and band match to construct devices and then research their spin filter efficiency. The spin filter efficiency can be improved effectively either by an appropriate gate voltage at Co₂Si region, or by series connection. In both cases the filter efficiencies are much larger than two-dimensional prepared Fe₃GeTe₂spin valve and ferromagnetic metallic chairlike O-graphene-H. Also at a quite small bias, we obtain a comparable spin polarized current as those obtained in Fe₃GeTe₂spin valve and O-graphene-H obtained at a much larger bias.