Electronic properties and spintronic applications of carbon phosphide nanoribbons

Abstract

Carbon phosphide (CP) monolayer, a hybrid of graphene and phosphorene that simultaneously preserves their high electrical mobility, finite band gap, and air stability, has been successfully synthesized in a recent experiment. In this work, we study the electronic and transport properties of CP nanoribbons in $\ensuremath{\alpha}$-phase with different edge configurations using first-principle density functional theory simulation. We find that the electronic properties of the CP nanoribbon exhibit contrasting behaviors depending on the edge termination configurations. In the presence of hydrogen edge passivation, the nanoribbon mimics black phosphorus nanoribbons with field-effect-tunable band gap. Conversely, for a bare edge terminated by a phosphorus atom, the nanoribbon becomes graphene-like, exhibiting large spin splitting in the ferromagnetic state and can be tuned into a half metal under an external transverse electric field in the antiferromagnetic state. Intriguingly, when the external transverse electric field exceeds a critical value, the charge transport channel becomes strongly localized to only one edge, and the edge localization can be tuned by an external electric field. Leveraging on the unusual spin-resolved transport properties of the CP nanoribbon, we demonstrate the operation of a bipolar spin filter with exceptional spin polarization efficiency approaching 100%. Our findings reveal the potential of the CP nanoribbon as a spintronic material that fuses the strengths of both graphene and phosphorene.