Progressive structural and electronic properties of nano-structured carbon atomic chains

Ab initio calculations, based on the planewave pseudopotential method and the density functional theory, have been reported on the changes in the electronic and structural properties of short carbon atomic chains held rigidly between hydrogenated thin armchair graphene nanoribbons (N-a-AGNR) of dimer line numbers N-a = 4 and 5. We have considered chains of several lengths (n = 4-9 atoms) and with different forms of attachment with the AGNRs. It is found that odd-numbered chains are metallic in nature, with chemical bonding more like center dot center dot center dot C=C=C=C center dot center dot center dot (as in cumulene). Even numbered chains show semiconductor structure when held between 4-AGNR and semi-metallic nature when held between 5-AGNR, in both cases characterized by chemical bonding more like center dot center dot center dot C-C C-C C center dot center dot center dot (as in polyyne). (C) 2013 AIP Publishing LLC