  We propose a highly efficient silicene device for dual spin and valley
filtering. The device consists of two different barrier regions: the first is a
region under uniaxial strain, with an exchange field induced by adjacent top
and bottom magnetic insulators, while the second comprises of two ferromagnetic
stripes which produces a delta-function fringe magnetic field, and a gate
electrode to modify the electrochemical potential. For the first region, we
investigated the effect of the uniaxial strain in inducing angular separation
of the two valley spins in momentum-space, and further spin separation by the
spin dependent electric potential induced by the exchange field. We then
evaluated the delta-function magnetic field and electrochemical potential
combination in the second region to yield the transverse displacement for the
selection of the requisite spin-valley combination. We demonstrated the optimal
conditions in the first barrier to induce a highly anisotropic transmission
profile, which enables controllable and efficient filtering (> 90% efficiency)
by the second region for all four spin-valley combinations. Based on the
analytical results, we predict the feasibility of experimental realization of
dual spin-valley silicene-based filtering device.
