First-Principles Study on the Role of Doped In in Fe–Pd–In Systems

Electronic states, for example, atomic positions, orbital hybridization, etc. determine crystal structures and these physical properties. The most stable crystal structure of binary Fe–Pd systems is known as a L1₂-type crystal structure[1, 2]. However, according to our latest experimental studies, a new Mille-feuille-like Fe–Pd structure is synthesized by adding a small amount of In, implying that In is the key to stabilizing the new system.
We performed first-principles calculations for the In-doped FePd₃ systems in order to understand the role of In in terms of its stability. There are two symmetrically different sites for Pd in the new system, which are labeled e and g, and In prefers the e site. This result is consistent with our recent experiments. From our analysis, we find that the distance between Fe, Pd, and In is the key factor in stabilizing the new system.
[1] T. B. Massalski et al., Binary Alloy Phase Diagrams (ASM International, ed. 2, 1990).
[2] R. V. Chepulskii et al., PRB 85, 144201 (2012).