Structure and Stability of Ni-Encapsulated Si Nanotube

Using tight-binding molecular dynamics and ab initio methods, we predict the existence of a novel quasi-one-dimensional Ni−Si form in which a Si nanotube is stabilized by an encapsulation of the Ni chain. The resulting structure is found to be metallic with finite DOS at the Fermi level. Our work follows the recent experimental work showing that endohedral encapsulation of transition metal atoms stabilizes the Si polyhedral cage.