Electronic Properties of Alkali- and Alkaline-Earth-Intercalated Silicon   Nanowires
  We present a first-principles study of the electronic properties of silicon clathrate nanowires intercalated with various types of alkali or alkaline-earth atoms. We find that the band structure of the nanowires can be tuned by varying the impurity atom within the nanowire. The electronic character of the resulting systems can vary from metallic to semiconducting with direct band gaps. These properties make the nanowires specially suitable for electrical and optoelectronic applications. 
S. Sirichantaropass, V. M. Garc\'ia-Su\'arez, C. J. Lambert