Semiconductor to metal to half-metal transition in Pt-embedded zigzag graphene nanoribbons

The electronic and magnetic properties of Pt-embedded zigzag graphene nanoribbons (Pt-ZGNRs) are investigated using density-functional theory calculations. It is found that Pt-ZGNRs exhibit a semiconductor-metal-half-metal transition as the position of Pt substitutional impurities in the ribbon changes from the center to edge sites. This behavior can be attributed to the interaction between Pt impurities and edge states of ZGNRs, which governs the electron occupation of the edge states. The transition always occurs independent of ribbon width. However, Pt impurity concentration is important for obtaining this transition. Our results demonstrate that Pt-ZGNRs can be used as versatile electronic devices.