Carbon Nanoarch Encapsulating Fe Nanowire on Ni (111)
  We investigate the stable structures of Fe-filled single-walled carbon nanotubes (SWNTs) on Ni(111), using density functional theory calculations. We find stable geometries and electronic states for the nanotube on Ni(111). We propose the possibility that the C-C bonds of carbon nanotube are broken by Fe wire and Ni surface. That is, when Fe-filled SWNT(3, 3) adsorb on Ni(111) surface, SWNT transforms into arch-like structure. 
Melanie David, Tomoya Kishi, Masanori Kisaku, Hiroshi Nakanishi,   Hideaki Kasai