Theoretical investigation on the structural stability of GaAs nanowires with two different types of facets

The relative stability between the wurtzite and zinc blende structures in GaAs nanowires with View the MathML source facets and those of View the MathML source / View the MathML source facets is systematically investigated using our empirical interatomic potential calculations and first-principles calculations. Our calculations clarify that the wurtzite structure is stabilized over entire diameters range for nanowires with View the MathML source facets. In contrast, for nanowires consisting of View the MathML source facets, the zinc blende structure is favorable for diameters larger than 29 nm. This is because the surface energy difference between View the MathML source and View the MathML source surfaces is quite small compared to that between {1 1 1} and View the MathML source surfaces. The calculated results imply that the stability of nanowire side facets is a quite important factor determining the crystal structure.