Spin gapless semiconductor and half-metal properties in magnetic penta-hexa-graphene nanotubes

Penta-hexa-graphene (PHG) is the name given to a novel puckered monolayer of carbon atoms tightly packed into an inerratic mixing pentagonal and hexagonal network. Theoretically, it exhibits excellent electronic properties and can be rolled into penta-hexa-graphene nanotubes (PHGNTs). By using first-principles combined with density functional theory, the PHGNTs with two types of chirality and different diameters were studied. Studies show that not only the nanotubes have intrinsic magnetic properties, but also the magnetic ground state changes with the tube diameter. Interestingly, the nanotubes exhibit semiconducting properties that do not vary with chirality in the antiferromagnetic (AFM) state. And in the ferromagnetic (FM) state, the materials realize the transitions from metal to spin gapless semiconductors (SGS), and to semiconductor with the change of tube diameter. Furthermore, first-principles calculation shows that PHGNTs exhibit diverse electronic properties when the external electrical field is applied, ranging not only from semiconductor to SGS and to metal, but also from semiconductor to half-metal and to metal. Our simulations have an impact on their possible applications in spintronic devices.