Monoatomic aluminum nitride nanochains and nanorings: DFT studies

Employing density functional theory calculations, we have studied a series of AlN nanochains and nanorings. We chiefly found that the chains have linear construction with triplet spin state that tend to be converted to the stable rings. By increasing the length of chains they show more metallic character. The Al-N bonds of chains are alternatively changed but those of the ring is equivalent. The HOMO-LUMO energy gap of chains was predicted to be very narrow in comparison to that of the rings. Unlike the chains, the ring buildings show resonance behavior. Depending the number of AlN units (being odd or even), the rings show different electronic properties. The HOMO and LUMO of chains are destabilized and stabilized, respectively, by increasing the length. We compared our results with those of the corresponding BN nanostructures.