Covalent surface modification with electron-donating/accepting π-conjugated chains to effectively tune the electronic and magnetic properties of zigzag SiC nanoribbons

Abstract

By means of first-principles DFT computations, a simple and effective strategy was proposed to modulate the electronic and magnetic properties of zigzag SiC nanoribbons (zSiCNRs) via linking π-conjugated chains with electron-donating/withdrawing groups on the surfaces of the nanoribbons. This type of covalent surface modification can evidently induce electron transfer between the zSiCNR substrate and conjugated chain; typical donor–π–donor or donor–π–acceptor frameworks are formed in the composite zSiCNR systems. Therefore, similar to applying an electric field, linking the electron-donating/withdrawing π-conjugated chains can cause an evident change in the electrostatic potential of the substrate zSiCNRs; this can break the magnetic degeneracy of the zSiCNRs and endow these composite systems with either ferromagnetic metallicity or even ferromagnetic/antiferromagnetic half-metallicity. Moreover, all the studied systems also exhibit large negative formation energies, indicating their very high structural stabilities. These valuable findings can be advantageous for promoting the application of excellent SiC-based nanomaterials in spintronics and multifunctional nanodevices.