Constructing elastic and electric model of wurtzite nanowires

International audienceThe continuous model of hexagonal wurtzite nanowires is presented[1-4]. This model describes elastic and electric properties of the nanowire, and explicitly takes into account the surface effects using Gurtin-Murdoch elasticity theory. The parameters of the model are obtained via first principles atomistic calculation using the periodic Density Functional computer code CRYSTAL09. The calculations are carried out for nanowires with diameter up to 3.5 nm with the largest unit cell containing as much as 588 atoms. The hexagonal (wurtzite) ZnO, AlN and GaN nanowires are investigated. To obtain the (101̅ 0) surface parameters, a series of slab (2D) calculations is performed and the surface parameters are obtained by interpolation. It is demonstrated that the continuous model is able to accurately reproduce the available first principles calculations, both for elastic and piezoelectric properties. Further, the constructed model is used to predict the properties of larger nanowires, and to study the distortions (e.g. bending, see Figure 1), the studies that are not accessible via ab initio calculations. In all cases it is shown that surface plays an important role in the enhancement of nanowire properties compared to bulk materials