Efficient dual spin-valley filter in strained silicene

We propose a highly efficient dual spin-valley filter in silicene, consisting of two distinct regions. In the first region, angular separation of the two valley spins in momentum-space is induced by a uniaxial strain, with further spin separation induced by an exchange field. The second region acts as an extractor of the requisite spin-valley current by means of localized fringe magnetic fields and gate modulation of the electrical potential. We demonstrate controllable and highly efficient filtering (exceeding 90%) for all four spin-valley combinations based on realistic parameter values. We also discuss the feasibility of a practical silicene-based spin-valley filter. (C) 2015 The Japan Society of Applied Physics