Dihalogen edge-modification: an effective approach to realize the half-metallicity and metallicity in zigzag silicon carbon nanoribbons

By means of first-principles computations, we have systematically investigated the electronic and magnetic properties of the zSiCNR with not only homogeneous but also heterogeneous diatomic edge-modification by employing halogen atoms, where one edge is saturated by double halogen F/Cl atoms, and the other is terminated by single or double F/Cl/H atoms, respectively. The computed results reveal that this kind of edge-modification by dihalogen atoms can break the magnetic degeneracy of the pristine zSiCNR, and the intriguing electronic and magnetic behaviors invoking not only the antiferromagnetic (AFM) metallicity but also the AFM half-metallicity and ferromagnetic (FM) half-metallicity can be achieved. The decorated atoms at the C-edge of zSiCNR can play an important role in affecting the electronic and magnetic properties of the modified zSiCNR systems, and the heterogeneous asymmetric edge-modification by the halogen/hydrogen pair with great electronegative difference can more effectively strengthen the robustness of half-metallicity. Additionally, employing strong electron-withdrawing halogen atom to perform a diatomic edge-modification can also significantly lower the edge formation energy of the modified zSiCNR systems, endowing them with higher structural stability. Obviously, diatomic edge-modification with halogen atoms can be an effective strategy to modulate the electronic and magnetic behaviors of zSiCNRs, which can be of benefit in promoting excellent SiC-based nanomaterials in the application of spintronics and multifunctional nanodevices.