Enhance the stability of α-graphyne nanoribbons by dihydrogenation

Half metallicity was found in wider 13-zigzag-alpha-graphyne nanoribbon (Z alpha GYNR) (Yue et al., 2012). However, the half metallicity is very delicate because the energy difference between the ferromagnetic (FM) and antiferromagnetic (AFM) states of 13-Z alpha GYNRs is just 1.8 meV. Here we investigate the dihydrogenation effects in Z alpha GYNRs and armchair alpha-graphyne nanoribbons (A alpha GYNRs) systematically by the first-principles. For dihydrogenated Z alpha GYNRs, the energy difference between the AFM and FM configurations is greatly increased compared with that for monohydrogenated cases, and thus the AFM state of dihydrogenated Z alpha GYNRs becomes much more stable. What's more, stable half-metallicity is realized in the dihydrogenated 8-Z alpha GYNR under a minute electric field. This suggests that the dihydrogenated Z alpha GYNRs are more promising than monohydrogenated ones for spintronic devices. For A alpha GYNRs, dihydrogenation brings about a gap size hierarchy completely different from monohydrogenation. (C) 2014 Elsevier B.V. All rights reserved.