Cluster Assembled Metal Encapsulated Thin Nanotubes of Silicon

Using ab initio total energy calculations we demonstrate that the recently found metal encapsulated silicon clusters Si₁₂Be can be assembled to form hexagonal nanotubes of silicon. This is in contrast to undoped silicon structures that are distorted and have a tendency to agglomerate. The finite nanotubes have varying HOMO-LUMO gaps depending upon the length and amount of doping. However, infinite nanotubes are metallic, symmetric, and stable, making metal encapsulation a useful route to generate metallic silicon nanowires for miniature devices.