Magnetic and electronic properties of single-walled Mo₂C nanotube: a first-principles study

The structural, electronic, and magnetic properties of single-walled Mo₂C nanotubes are investigated by using first-principles calculations. We establish that single-walled Mo₂C nanotubes can be rolled up from a graphene-like Mo₂C monolayer with H- or T-type phase, i.e. H-Mo₂C and T-Mo₂C nanotubes. The armchair-type T-Mo₂C nanotubes are more energetically stable than H-Mo₂C nanotubes with the same diameter, while zigzag-type H-Mo₂C nanotubes are more energetically stable than T-Mo₂C nanotubes. In particular, (8, 0) H-Mo₂C nanotube are more stable than Mo₂C monolayer due to structural deformation. All Mo₂C nanotubes are magnetic metals, independent of their chirality, and the magnetic moments of Mo atoms in the outer layer are larger than the inner. The ionic and metallic bonds in Mo₂C nanotubes and delocalized electrons around Mo atoms lead to the versatile electronic and magnetic properties in them, endowing them potential applications in catalysts and electronics.