Behaviors and interactions of La atom with other foreign substitutional atoms (Al, Si, Ti, V, Cr, Mn, Co, Ni, Cu, Nb or Mo) in iron based solid solution from first principles

The behaviors and interactions of La atom with the most frequent foreign substitutional atoms (FSAs, i.e. Al, Si, Ti, V, Cr, Mn, Co, Ni, Cu, Nb or Mo) in iron based solid solution are investigated using first principles calculations based on the density functional theory. Big positive values are obtained for the substitution energy of a La atom in bcc Fe and the sum of the Fe atoms’ relaxations around La atom. Our calculated tendency of lattice expansion for Fe–FSA alloys is in agreement with experimental data. Binding energies indicate that the interaction is attractive for La–Cu, close to zero for La–Co/Ni, and repulsive for La–FSA (the FSA is Al, Si, Ti, V, Cr, Mn, Nb or Mo), respectively. The density of states of all FSAs presents a hybridization around −16.3 eV because of the interaction of La atom with another FSA. Negative populations and antibonding states exist in both La–FSA and La–Fe bonds.