On the properties of surface reconstructed silicon nanowires

We study by means of density-functional calculations the role of lateral surface reconstructions in determining the electrical properties of (100) silicon nanowires. The different lateral reconstructions are explored by relaxing all the nanowires with crystalline bulk silicon structure and all possible ideal facets that correspond to an average diameter of 1.5 nm. We show that the reconstruction induces the formation of ubiquitous surface states that make the wires semi-metallic or metallic.