Theoretical investigation on the structural stability of GaP nanowires with {111} facets

The structural stability of GaP nanowires (NWs) with {111} facets including twin planes is systematically investigated using our empirical potentials which incorporate the electrostatic interaction between surface cations and anions. The cohesive energy of GaP NWs for diameter of ∼30 nm demonstrates that the wurtzite structure is the most stable over entire diameter range. This is because the electrostatic interaction between surface cations and anions is dominant around twin planes, resulting in the small energy deficit compared to that on polar {111} facets. By comparing the cohesive energy of GaP NWs consisting of {111}/{11¯00} facets with that of {11¯0}/{112¯0} facets, the NWs consisting of {11¯0}/{112¯0} facets are found to be favorable than those consisting of {111}/{11¯00} facets over entire diameter range. These results imply that growth processes such as vapor-liquid-solid mechanism could affect on the formation of NWs consisting of {111}/{11¯00} facets.