Edge effect induce spin-gapless semiconducting and half-metallic properties of N-doped zigzag graphene nanoribbons

Abstract

Graphene nanoribbons with mixed edge structures are promising candidate materials for the next generation of nanoelectronics due to their unique and peculiar physical and chemical properties, as well as their interesting and tunable electronic structures. Here, we designs and calculates a series of periodic edge N-doped ZGNRs using first principles calculations based on density functional theory. The band gap of these ZGNRs can be adjusted from metal to semiconductor, by the periodic length of the nanobands, and the number and interval distance of N atom doping. Among them, 6-ZGNR-(1,3) is a metallic, 6-ZGNR-(1,4) and 6-ZGNR-(2,4) are half-metallic, 6-ZGNR-(2,5) and 6-ZGNR-(3,5) are SGS, and 6-ZGNR-(3,6) is a magnetic semiconductor. We projected band structures into p_x orbitals of edge C and N atoms separately, and found that the energy near the Fermi level in 6-ZGNR-(1,4) is mainly contributed by edge C atoms, while 6-ZGNR-(3,5) is contributed by edge N atoms. This indicates that N atom doping plays a major role in the transition of spin polarization properties. Our studies suggest that it will have significant theoretical significance and practical value in the application of spintronic devices.