Magnetic Properties of Transition Metal Nanoparticles: A DFT-Inhomogeneous-DMFT Analysis

To include electron-electron correlation effects in the nanosystem we are proposing a combined density-functional-theorydynamical-mean-field-theory (DFT + DMFT) approach, which we have recently shown to be suitable for including correlation effects in small (2-5 atoms) Fe and FePt clusters [1]. This method has several advantages as compared to the widely used DFT + U approach, the most important of which is that it takes into account dynamical correlation effects automatically. We find that the inclusion of dynamical effects leads to a reduction in the cluster magnetization (as compared to results from DFT + U ) and that, the magnetization values agree well with experimental estimations. We will present results of application of this formalism to examine the size dependent magnetic properties of Fe15, Fe17 and Fe19 clusters. For the above we have developed a computational code that should be capable of calculating the magnetic properties of systems containing hundreds of atom.