First-principles study of half-fluorinated silicene sheets

Abstract

The structural, electronic and magnetic properties of half-fluorinated silicene sheets are investigated using first-principles simulation. Three conformers of half-fluorinated silicene are studied and their properties are compared. Half-fluorinated silicene sheets with zigzag, boat-like or chair-like configurations are confirmed as dynamically stable based on phonon calculations. Upon the adsorption of fluorine, energy gaps open in both zigzag and boat-like conformations. They are found to be direct-gap semiconductors. The half-fluorinated silicene with chair-like configuration shows an antiferromagnetic behavior which is mainly induced by the un-fluorinated Si atoms. Furthermore, when isotropic strain is uniformly exerted onto chair-like half-fluorinated silicene, the energy difference between ferromagnetism states and antiferromagnetism states decreases with increasing compression strain from 0% to −6% or increasing tension strain from 0% to 6%. These results demonstrate that fluorination with different atomic configurations is an efficient way to tune the electronic structures and properties of silicene sheets and highlight the potential of half-fluorinated silicene for spintronics.