Efficient dual spin-valley filter in strained silicene

Abstract

We propose a highly efficient silicene device for dual spin and valley\nfiltering. The device consists of two different barrier regions: the first is a\nregion under uniaxial strain, with an exchange field induced by adjacent top\nand bottom magnetic insulators, while the second comprises of two ferromagnetic\nstripes which produces a delta-function fringe magnetic field, and a gate\nelectrode to modify the electrochemical potential. For the first region, we\ninvestigated the effect of the uniaxial strain in inducing angular separation\nof the two valley spins in momentum-space, and further spin separation by the\nspin dependent electric potential induced by the exchange field. We then\nevaluated the delta-function magnetic field and electrochemical potential\ncombination in the second region to yield the transverse displacement for the\nselection of the requisite spin-valley combination. We demonstrated the optimal\nconditions in the first barrier to induce a highly anisotropic transmission\nprofile, which enables controllable and efficient filtering (> 90% efficiency)\nby the second region for all four spin-valley combinations. Based on the\nanalytical results, we predict the feasibility of experimental realization of\ndual spin-valley silicene-based filtering device.\n