Electron transport channels and their manipulation by impurity in armchair-edge graphene nanoribbons

Abstract

Under the scheme of the nonequilibrium Green’s function combined with the tight-binding approximation, we study electron transport properties in different atomic chains of an armchair-edged graphene nanoribbon (AGNR) and their manipulation using a single substitutional impurity atom. By calculation and analysis of the local bond currents between nearest atom sites in the AGNR, we find that electron transport along two armchair-edged chains is more active than that along other chains for any clean AGNR. For a metallic AGNR, interestingly, there exists a series of parallel distributed major channels for the low-energy electron transport. Further, the transport properties of these channels can be manipulated by a single substitutional impurity atom with different strength and locating position, e.g., a suitable impurity can cause a selected channel to be closed completely while others still open. However, in the high-energy regime these independent channels disappear, and a metallic AGNR becomes entirely metallic in this case. The findings here suggest that an AGNR may be used as a multi-channel plane material in the future nanoelectronic technology.