Structural, electronic and magnetic properties of various nanosystems : molecular dynamics simulations and density functional theory calculations

Sholejh, Alaei
In this study, we aim to investigate the structural, magnetic and electronic properties of various nanosystems using molecular dynamics simulation technique and density functional theory calculations. In the first part, iron oxide nanostructures (nanorods, clusters and nanoparticles) were considered. We applied strain, at different temperatures, on nanorods in order to study stability of iron oxide nanorods using molecular dynamics simulation. Furthermore, radial distribution functions of iron oxide nanoparticles at different temperatures using the same mentioned method are calculated. Besides, the electronic and magnetic properties of (Fe2O3)n (n=2-5) clusters were studied using Density Functional Theory. It came out that the most stable structures for n=2, 3 were ferromagnetic and for n=4, 5 were antiferromagnetic. It was found that by increasing ‘n’ the binding energy (Eb) increased, while such an observation was not seen for n=4 and n=5 and the relative energy was equal in these cases. An interesting result was that one of the states for n=4 (n4-1) was a half-metallic anti ferromagnetic, which is important in spintronics applications. The last part of this survey was pursuing the effect of transition metal atoms (Fe-Co-Ni) adsorptions on magnetic and electronic properties of graphyne nanotubes. Magnetic atom doped graphyne nanotubes show interesting magnetic properties.