First principle study on the bonding mechanism of nanoring structure Ga8As8 L. Z. Sun, X. S. Chen, X. H. Zhou, Y. L. Sun, Zh. J. Quan and Wei Lu Eur. Phys. J. D, 34 1-3 (2005) 47-50 Published online: 13 July 2005 DOI: 10.1140/epjd/e2005-00116-7