Geometric evolution, electronic structure, and vibrational properties of <scp>ScGen</scp>− (<scp>n</scp> = 6–17) anion clusters: A <scp>DFT</scp> insight

In this work, we investigated the structural evolution, electronic and magnetic properties of Cr2Gen− clusters for n = 15–20 by using density functional theory (DFT) calculations. Low‐energy structures for these clusters were fully searched through a self‐developed genetic algorithm code combined with DFT calculations. The calculations show that all the two Cr atoms prefer to stay together to form a strong CrCr bond, which—except for size 20—is shorter than the nearest neighbor distance in Cr bulk. Sizes 15 and 16 adopt a wheel‐like structure as the structural motif with the extra Ge atoms capped on the top, while larger sizes (n = 17–20) prefer fullerene‐like Cr2@Ge12 motifs. From the results of the average binding energies of Cr2Gen−, one can conclude that it is easier to form larger size clusters. In these lowest‐lying isomers except for size 16, the two Cr atoms contribute opposite magnetic moments for the total magnetic moments of 1 μB, showing an antiferromagnetic state.

Cr₂Ge_n⁻ (n = 15–20) clusters with two Cr atoms exhibited antiferromagnetic coupling

Wang

2023

Aromatic and magnetic properties in a series of heavy rare earth‐doped Ge₆ cluster anions

Zhang,

Wang,

et al. 2024

A series of pentagonal bipyramidal anionic germanium clusters doped with heavy rare earth elements, (RE = Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu), have been identified at the PBE0/def2‐TZVP level using density functional theory (DFT). Our findings reveal that the centrally doped pentagonal ring structure demonstrates enhanced stability and heightened aromaticity due to its uniform bonding characteristics and a larger charge transfer region. Through natural population analysis and spin density diagrams, we observed a monotonic decrease in the magnetic moment from Gd to Yb. This is attributed to the decreasing number of unpaired electrons in the 4f orbitals of the heavy rare earth atoms. Interestingly, the system doped with Er atoms showed lower stability and anti‐aromaticity, likely due to the involvement of the 4f orbitals in bonding. Conversely, the systems doped with Gd and Tb atoms stood out for their high magnetism and stability, making them potential building blocks for rare earth‐doped semiconductor materials.

Magnetic properties of CrMnGe_n (n = 3–20) clusters

Wang,

Zhao,

Guo

et al. 2024

Due to the potential applications in next‐generation micro/nano electronic devices and functional materials, magnetic germanium (Ge)‐based clusters are receiving increasing attention. In this work, we reported the structures, electronic and magnetic properties of CrMnGen with sizes n = 3–20. Transition metals (TMs) of Cr and Mn tend to stay together and be surrounded by Ge atoms. Small sized clusters with n ≤ 8 prefer to adopt bipyramid‐based structures as the motifs with the excess Ge atoms absorbed on the surface. Starting from n = 9, the structure with one TM atom interior appears and persists until n = 16, and for larger sizes n = 17–20, the two TM atoms are full‐encapsulated by Ge atoms to form endohedral structures. The Hirshfeld population analyses show that Cr atom always acts as the electron donor, while Mn atom is always the acceptor except for sizes 3 and 6. The average binding energies of these clusters increase with cluster size n, sharing a very similar trend as that of CrMnSin (n = 4–20) clusters, which indicates that it is favorable to form large‐sized clusters. CrMnGen (n = 6, 13, 16, 19, and 20) clusters prefer to exhibit ferromagnetic Cr–Mn coupling, while the remaining clusters are ferrimagnetic.