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 {111}/{11¯00} facets and those of {11¯0} / {112¯0} 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 {111}/{11¯00} facets. In contrast, for nanowires consisting of {11¯0}/{112¯0} facets, the zinc blende structure is favorable for diameters larger than 29 nm. This is because the surface energy difference between {11¯0} and {112¯0} surfaces is quite small compared to that between {1 1 1} and {11¯00} surfaces. The calculated results imply that the stability of nanowire side facets is a quite important factor determining the crystal structure.