Dependence of transport on adatom location for armchair-edge graphene nanoribbons

摘要

We study the transport property for armchair-edge graphene nanoribbons(AGNRs) with an adatom coupling to a semi-infinite quantum wire. Using thenonequilibrium Green's function approach with tight-binding approximation, wedemonstrate that the tunneling current through the system is sensitivelydependent on both the AGNR width and adatom location. Interestingly, when theadatom locates onto a carbon atom in the 3$j$th chain from the edge of ametallic AGNR, the system shows a transmission gap accompanied by a thresholdvoltage in $I-V$ curve like a semiconducting AGNR. This effect may be useful inscanning tunneling microscopy experimental characterization on graphenesamples.