Robust Ferromagnetism in Silicene Nanoflakes through Patterned Hydrogenation

TL;DR

This study investigates how patterned hydrogenation affects the electronic and magnetic properties of silicene nanoflakes, revealing tunable ferromagnetism and potential applications in spintronics through first principles calculations.

Contribution

It demonstrates that hydrogenation can reversibly and controllably induce strong ferromagnetism in silicene nanoflakes, a novel approach for spintronic device design.

Findings

Triangular SiNFs switch from ferrimagnetic to ferromagnetic with hydrogenation.

Hexagonal SiNFs become ferromagnetic upon hydrogenation.

Half hydrogenated SiNFs exhibit large, size-dependent spin moments.

Abstract

Considerably different properties emerge in nanomaterials as a result of quantum confinement and edge effects. In this study, the electronic and magnetic properties of quasi zero dimensional silicene nanoflakes (SiNFs) are investigated using first principles calculations. Whilst the zigzag edged hexagonal SiNFs exhibit nonmagnetic semiconducting character, the zigzag edged triangular SiNFs are magnetic semiconductors. One effective method of harnessing the properties of silicene is hydrogenation owing to its reversibility and controllability. From bare SiNFs to half hydrogenated and then to fully hydrogenated, a triangular SiNF experiences a change from ferrimagnetic to very strong ferromagnetic, and then to non-magnetic. Nonetheless, a hexagonal SiNF undergoes a transfer from nonmagnetic to very strong ferromagnetic, then to nonmagnetic. The half hydrogenated SiNFs produce a large spin moment that is directly proportional to the square of the flakes size. It has been revealed that the strong induced spin magnetizations align parallel and demonstrates a collective character by large range ferromagnetic exchange coupling, giving rise to its potential use in spintronic circuit devices. Spin switch models are offered as an example of one of the potential applications of SiNFs in tuning the transport properties by controlling the hydrogen coverage.