Efficient Dual Spin-Valley Filter In Strained Silicene

TL;DR

This paper introduces a highly efficient silicene device that uses strain, magnetic fields, and electrochemical potential to achieve controllable dual spin and valley filtering with over 90% efficiency.

Contribution

It presents a novel dual spin-valley filter design in silicene utilizing uniaxial strain and magnetic fields, demonstrating high efficiency and controllability.

Findings

Achieves over 90% filtering efficiency for all spin-valley states.

Demonstrates controllable angular separation of valley spins via uniaxial strain.

Predicts experimental feasibility of the proposed device.

Abstract

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.