Half-metallicity in aluminum-doped zigzag silicene nanoribbons

TL;DR

This study uses first-principles calculations to explore how aluminum doping in zigzag silicene nanoribbons induces half-metallicity, with potential applications in spintronic devices, depending on dopant position and concentration.

Contribution

It demonstrates that substitutional Al doping can induce half-metallicity in zigzag silicene nanoribbons, revealing position-dependent spin transport properties and effects of multiple dopants.

Findings

Single Al doping can induce half-metallicity.

Dopant position affects spin transport channels.

Multiple dopants suppress half-metallicity and magnetic properties.

Abstract

The spin-dependent electronic structures of aluminum-(Al) doped zigzag silicene nanoribbons (ZSiNRs) are investigated by first-principles calculations. When ZSiNRs are substitutionally doped by a single Al atom on different sites in every three primitive cells, they become half-metallic in some cases, a property that can be used in spintronic devices. More interestingly, spin-down electrons can be transported at the Fermi energy when the Al atom is placed on the sub-edge site. In contrast, spin-up electrons can be transported at the Fermi energy when the ZSiNRs are doped on sites near their center. The magnetic moment on edge is considerably suppressed if the Al atom is doped on edge or near-edge sites. Similar results are obtained for a phosphorus-(P) and boron-(B) doped ZSiNR. When two or more Si atoms are replaced by Al atoms, in general the half-metallic behavior is replaced by a metallic, spin gapless semiconducting or semiconducting one. When a line of six Si atoms, along the ribbon's width, are replaced by Al atoms, the spin resolution of the band structure is suppressed and the system becomes nonmagnetic.