Switching modulation of spin transport in ferromagnetic tetragonal silicene

TL;DR

This paper investigates the electronic and spin transport properties of ferromagnetic tetragonal silicene nanoribbons, demonstrating controllable spin currents and phase transitions relevant for spintronic device applications.

Contribution

It introduces a novel four-terminal device configuration enabling control of spin-dependent conductance using switches, advancing spintronic technology.

Findings

Spin-dependent conductance can be manipulated by electric field and exchange interactions.

A phase transition from semimetallic to semiconducting state is achievable by changing nanoribbon width.

The device can realize spin filtering and zero conductance states with high spin polarization.

Abstract

We study the band structure and transport properties of ferromagnetic tetragonal silicene nanoribbons by using the non-equilibrium Green's function method. The band structure and spin-dependent conductance are discussed under the combined effect of the external electric field, potential energy, exchange field and the spin-orbit coupling. One can easily realize a phase transition from a semimetallic to a semiconducting state by changing the transverse width of the nanoribbon. Separation of spin-dependent conductances arises from the effect of exchange field and the spin-orbit coupling, while zero-conductance behaviors exhibit spin-dependent band gaps induced by the electric field. We propose a device configuration of four-terminal tetragonal silicene nanoribbon with two central channels. It is found that spin current can be controlled by utilizing two switches. The switch with a high potential barrier can block electrons flowing from the central scattering region into other terminals. Interestingly, applying only one switch can realize spin-dependent zero conductance and large spin polarization. Two switches can provide multiple operations for controlling spin-dependent transport properties. The two-channel ferromagnetic tetragonal silicene nanoribbon can realize an effective separation of spin current, which may be a potential candidate for spintronic devices.