We report a genetic algorithm approach combined with ab initio calculations to determine the structure of hydrogenated 110 Si nanowires. As the number of atoms per length increases, we find that the cross section of the nanowire evolves from chains of six-atom rings to fused pairs of such chains to hexagons bounded by {001} and {111} facets. Our calculations predict that hexagonal wires become stable starting at about 1.2 nm diameter, which is consistent with recent experimental reports of nanowires with diameters of about 3 nm.

Hydrogenated 110 silicon nanowires evolve into hexagonal structures with stable stability starting at 1.2 nm diameter, consistent with experimental reports of nanowires with diameters of 3 nm.

Magic structures of h-passivated 110 silicon nanowires.

Key Takeaway: Hydrogenated 110 silicon nanowires evolve into hexagonal structures with stable stability starting at 1.2 nm diameter, consistent with experimental reports of nanowires with diameters of 3 nm.