Tunable band gap, magnetoresistance and pseudo-magnetoresistance in silicene-based nanodevices

Abstract

Spin-dependent transport in two terminal zigzag silicene nanoribbon is investigated numerically in the presence of spin-orbit interactions, external spin splittings or exchange fields, and perpendicular electric field. We show by applying an exchange field, a tunable band gap emerges which depends on the exchange field vector angle with the plane of nanoribbon. Such behavior is interpreted using the low-energy Hamiltonian of the silicene which indicates qualitative agreement with results obtained from lattice model. Moreover, it is found that by decreasing the width of nanoribbon larger band gaps are achievable which can be promising for nanoelectronic applications. On the other hand, by imposing exchange fields inside the electrodes, the magnetoresistance of the junction is investigated. As a main result we observe that when the Rashba interaction becomes stronger the magnetoresistance decreases but it is not fully suppressed. Finally, in the presence of perpendicular electric fields applied to the electrodes, depending on their relative configuration, the so-called pseudomagnetoresistance is calculated. Our results indicates that the conductance of the silicene nanoribbon significantly differs between the parallel and anti-parallel configurations of electric fields in the electrodes.