All-Electrical Manipulation for Magnetism and Fano Resonance in the Molecular Junction Based on a Covalently Functionalized Graphene Nanosheet

Achieving all-electrical writing and reading of magnetization states in molecular spintronics devices is desirable for miniaturized electrical circuits. By means of the first-principles method, gate-modulated spin-dependent transport is investigated in a molecular junction based on a covalently functionalized graphene nanosheet. Induced by the localized spin-split flat band states, the transmission spectra exhibit obvious spin-resolved Fano resonance features. By exploiting the unique Fano line shape, a high/low conductance switch and spin polarization reversal from 93% to -90% are realized under the control of electrical gating. When the gate voltage reaches critical values, a magnetic-nonmagnetic transition occurs within the graphene nanosheet. The mechanism is explored by tracing the gating-induced change in the molecular states. Furthermore, efficient spin-dependent transport and gate tuning spin polarization under bias voltage are revealed. Our work provides a fantastic opportunity to design high-performance all-electrical spintronics devices.