armchair nanoribbons with transition metals*

Armchair WS₂ nanoribbons are semiconductors with band gaps close to 0.5 eV. When a W atom is replaced by a transition metal, impurity states can have tremendous effect on the overall electronic structures. By using first-principles calculations based on density functional theory, we investigated substitutional of Ti, V, Cr, Mn, Fe, Co for WS₂ ribbons of different widths. We found that Fe-doped ribbons have two-channel conduction separately in the middle part of the ribbon and at the edges. Co-doped ribbons are turned in to spin filters, having 100% spin-polarized conductions. These results should be useful for nano-electronic circuit design.