Determine the supercell structures of related Fe–Pd–Te compounds

Determine the supercell structures associated with the superlattice Bragg peaks observed in FePd2Te2 and FePd2.5Te2, including whether they arise from complex Fe/Pd ordering or interstitial Pd in the van der Waals gaps.

Background

The paper compares Fe0.68Pd0.80Te with the related Fe–Pd–Te compounds FePd2Te2 and FePd2.5Te2, which also exhibit superlattice Bragg peaks. Although the authors establish a 3×3×3 Pd-vacancy order in Fe0.68Pd0.80Te, they state that the structural origin and detailed supercells of the related compounds remain unresolved. Possible explanations include complex ordering of Fe and Pd atoms or interstitial Pd occupying the van der Waals gaps.

References

Recently, superlattice Bragg peaks were also identified in two other Fe-Pd-Te ternary compounds FePd2Te2 and FePd2.5Te2. The details of their supercells were not known but proposed to be associated with the possible complex ordering of Pd/Fe atoms or the interstitial Pd in the van der Waals gaps.

— Vacancy Order and Physical Properties of a Ternary Compound Fe0.68Pd0.80Te with an α-Fe1+xTe-Type Structure  (2609.11441 - Shi et al., 10 Sep 2026) in Section 2, “Vacancy order”