Ab initio calculations of interaction between Ni and Si in α-Fe

Ab initio calculations based on the density functional theory were performed to investigate the interaction between Ni and Si in the body-centred cubic Fe system. The Ni-Si interaction was first evaluated in the framework of small Ni-Si clusters, then followed by detailed analyses. The calculations showed that even though the formation of pure Ni clusters was not energetically favoured, the presence of Si can stabilize the Ni clusters through attractive binding energies. Si atom sitting on lattice site or interstitial site was studied. In the case of Si sitting on interstitial site, the contribution of lattice distortion to the cluster binding energy may be emphasized. The electronic structure analyses of the attractive Ni-Si binding indicated that chemical interaction between Ni and Si atoms can form.