Investigating the structural, electronic, and magnetic properties of Fe2@Genα (α = 0, +1, −1, n = 1–13) nanoclusters: DFT insights

Abstract

In this study, we perform a comprehensive investigation of charged iron-germanium nanoclusters, denoted as Fe₂Ge_n^α (α = 0, ±1; n = 1–13), using density functional theory (DFT). Our primary focus lies in understanding their structural, electronic, and magnetic characteristics. The results reveal a progressive increase in binding energy with cluster size, indicating enhanced stability as the cluster size increases. Notably, Fe₂Ge₁₀ and Fe₂Ge₁₂ exhibit exceptional thermodynamic stability, suggesting “magic number” behavior for these specific compositions. The highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap systematically narrows with increasing cluster size, ranging between 1.5 and 2.5 eV for both neutral and anionic clusters, which points to tunable electronic properties. Structural analysis indicates that the incorporation of Fe atoms into germanium-based cage-like frameworks significantly enhances the overall stability of the clusters. Moreover, charge transfer from Fe to surrounding Ge atoms plays a critical role in modulating both electron distribution and magnetic behavior. Most clusters exhibit a total magnetic moment of approximately 6 μ_B, with the notable exception of Fe₂Ge₉, which displays a reduced moment of 4 μ_B. These insights into the structure–property relationships of Fe–Ge nanoclusters highlight their promise for applications in nanotechnology, particularly in the rational design of functional cluster-based materials.