Tailoring the Electronic Structure of Zigzag Graphene Nanoribbons via Cu Impurities

Abstract

We employed density functional theory based spin polarised calculations to explore the structural stability and electronic properties of ZGNR using Cu as a terminating element as well as a substitutional dopant at various sites. In both the cases (termination and doping) Cu impurities affect the electronic properties of nanoribbons in a different way. The calculated formation energy indicates that all the structures are energetically feasible except the both edges Cu-doped ribbons. Binding energy analysis confirms that Cu impurities are strongly bound to ZGNR in all considered configurations. Moreover, ribbon edge is regarded as the most feasible site for substitutional Cu atoms in ZGNR. The electronic properties of ZGNR are sensitive to the position of Cu atoms and the ribbon width. It is revealed that ZGNR can be made semiconducting, semi-metallic, half metallic or purely metallic in nature merely by changing the ribbon width or the position of Cu atoms. The predicted half metallicity for one edge Cu-terminated ZGNR is robust against the choice of exchange correlation potential.