Abstract

Doping provides an effective means to tailor the chemical properties of clusters and construct novel functional materials. However, the specific effects of rare-earth doping on the structural evolution and electronic properties of semiconductor clusters remain unclear. To address this, we systematically investigated the structures, growth patterns, electronic properties, and spectroscopic characteristics of Gen− and LaGen0/− clusters (n = 10–20) using the ABCluster global search method combined with the mPW2PLYP double-hybrid density functional. Notably, the global minimum (GM) structures of Gen− (n = 12–20), confirmed based on calculated energies and measured photoelectron spectroscopy data, differ from previously reported structures. Starting from n = 12, the GM structure of the Gen− cluster can be considered as formed by attaching an additional Ge(n–9) or Ge(n–10) subcluster to a capped tetragonal antiprism Ge9 (or dicapped tetragonal antiprism Ge10) subunit. The evolution pattern of LaGen (n = 10–19) clusters can be viewed as substitutional structures, in which a La atom substitutes one Ge atom in the Ge(n+1)− cluster. At n = 20, a cage-like structure is formed. For LaGen− (n = 10–19), when n = 10–12 and 18, the structures are linked configurations, where the La atom connects two Ge subclusters. For the remaining clusters, although their global minimum structures tend toward linked configurations, they are fundamentally substitutional in nature. The GM structure of LaGe20− is an encapsulated configuration, with the La atom encapsulated at the center of the Ge cage. The average binding energies, relative stabilities, and HOMO–LUMO energy gaps of the clusters were evaluated. The photoelectron spectra of LaGen− (n = 10–20) and the UV–vis absorption spectrum of the LaGe20− cluster were simulated. The results demonstrate that the LaGe20− superatom cluster with high Ih symmetry exhibits favorable optical properties, along with excellent chemical and thermodynamic stability, suggesting its potential as a promising building block for further exploration in optoelectronic-related applications.

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