Modelling of pine-tree nanowires
Nanowires are thin wires (e.g. metal) which are severely restricted in 2 dimensions of space and show a one-dimensional quantization of conductivity. They have a length to diameter ratio of about 1000 and a thickness of some nanometers. Often, they grow defect-free in a catalytic reaction from a substrate, but recently interesting patterns have been observed in situations, where the wires grow in a controlled way with a screw dislocation inside the trunk. As had been predicted earlier, this leads to the so called Eshelby twist of the wire, which stabilizes the dislocation in the center of the wire, and experimental findings suggest that this torsion favors the emergence of sidebranches. In this study we use finite element methods and Ginzburg-Landau models to investigate the dislocation motion and morphology evolution of the nanowire numerically and compare the results to theoretical predictions.This work is jointly done at the Max-Planck institute for iron research in Düsseldorf and ICAMS, Bochum.