Spin- and valley-dependent transport through arrays of ferromagnetic silicene junctions

TL;DR

This paper investigates how arrays of ferromagnetic silicene junctions can control spin and valley polarized transport through electric and magnetic fields, revealing resonances, gaps, and polarization effects useful for electronic switching.

Contribution

It introduces a detailed analysis of spin- and valley-dependent transport in silicene with multiple barriers, highlighting electric field-controlled switching and polarization tuning.

Findings

Resonances and dips in conductance depend on potential and exchange field.

Electric field widens the transport gap, enabling current switching.

Spin and valley polarizations can reach 100% and are tunable by external fields.

Abstract

We study ballistic transport of Dirac fermions in silicene through arrays of barriers, of width $d$, in the presence of an exchange field $M$ and a tunable potential of height $U$ or depth $-U$. The spin- and valley-resolved conductances as functions of $U$ or $M$, exhibit resonances away from the Dirac point (DP) and close to it a pronounced dip that becomes a gap when a critical electric field $E_z$ is applied. This gap widens by increasing the number of barriers and can be used to realize electric field-controlled switching of the current. The spin $p_s$ and valley $p_v$ polarizations of the current near the DP increase with $E_z$ or $M$ and can reach 100\% for certain of their values. These field ranges widen significantly by increasing the number of barriers. Also, $p_s$ and $p_v$ oscillate nearly periodically with the separation between barriers or wells and can be inverted by reversing $M$.