Fluorine edge decoration on zigzag silicene nanoribbons

Abstract

Abstract We used the density functional theory (DFT) to explore the effects of fluorine (F) edge decoration on zigzag silicene nanoribbons (ZSiNR). Due to the strong electron affinity of fluorine atoms, a strong chemical bond between Si atoms and F atoms is formed. The formation energy also indicated that the fluorination configurations had higher stability than for the ZSiNR. The fluorination sites at the edges efficiently modulate the electronic and magnetic properties of the ZSiNR. In particular, we found a significant change from a metallic to a semiconductor characteristic in asymmetric edge fluorinated ZSiNR, in a mono-fluorinated system with one single edge, which was attributed to the weakening of the σ-π mixing effect. In contrast, a half-metallic character with a 100% spin polarization was induced in another other two full asymmetric fluorination systems due to the contribution from the F-Py, F-Pz, and Si-Py orbitals. All asymmetric fluorinations maintained a ferromagnetic character. Symmetric edge fluorinated ZSiNR maintained a ferromagnetic metallic characteristic or an antiferromagnetic semi-conductor characteristic due to the Coulomb repulsion from both edges. The interesting and useful physical properties in ZSiNR with edge fluorination including the half-metallic character and the spin polarization implied that edge-fluorinated ZSiNR can be effectively used in spintronic devices.