Structural stability and evolution of terbium‐doped silicon clusters and influence of 4f → 5d electronic transition mechanism on magnetism and appearance of photoelectron spectroscopy for TbSi_n^0/− (n = 6‐18) clusters

Abstract

The global minimal structures of terbium-doped Si clusters and their anions TbSi n 0/− (n = 6-18) are confirmed by employing the ABCluster unbiased global search technique combined with a B2PLYP double-hybrid density functional and comparing consistency of simulated and experimental photoelectron spectroscopy (PES). The results demonstrated that structural evolution patterns for neutral clusters prefer Tb-substitutional to Tb-encapsulated configuration starting from n = 16. While for the corresponding anionic clusters, the growth pattern adopts Tb-linked structures to encapsulated motif. The Natural Population Analysis revealed that the 4f electrons of Tb atom in TbSi n 0/− (n = 6-18) clusters participate in bonding. The way to participate in bonding is one 4f electron transition to 5d orbital ([Xe]6s 2 4f 9 ! [Xe]6s 2 4f 8 5d 1), which significantly affects the cluster's magnetism and appearance of PES. The total magnetic moments of neutral TbSi n and the corresponding anions maintain at 7 μB and 6 μB, respectively, which are larger than that of an isolated Tb atom. The HOMO-LUMO energy gap, relative stability, and chemical bonding analysis demonstrated that superatomic TbSi 16 − cluster is a magic cluster with fine thermodynamic and moderate chemical stability. K E Y W O R D S terbium-doped Si clusters, structural evolution patterns, cluster's magnetism 1 | INTRODUCTION Rare earth (RE) is known as the industrial "gold." RE-doped semiconductors such as silicon exhibits novel light electron magnetic and chemical properties and yields interesting features that are extremely useful in broad applications, from microelectronic industries to energy, materials, and chemical industries. For instance, erbium silicides are the excellent silicon-based photonic source: the light emitting diode, fiber amplifier, or device of the photomedicine. [1] NdFeB magnets are widely used in small size direct current motor, hard disks, mobile phones, battery-powered tools, and other electronic products. [2,3] RE silicides play a vital role in refining, desulfurization, neutralizing low-melting harmful impurities, and improving the properties of steels. [4] Terbium silicide is an ideal device, which has immeasurable potential in field emission cathode, hydrogen storage material, internal photoemission infrared detector, and so forth. It is also used in semiconductor industry as large-scale integrated circuits, Ohmic contacts, and rectifying contacts, owing to the interfaces of terbium and silicon have good lattice matching, sharp interfaces, low Schottky barrier heights, high conductivity, and excellent thermal stability. [5,6] Furthermore, terbium silicides can be formed by a self-assembly process, which is a powerful tool overcoming the miniaturization limit of traditional lithography-based fabrication methods of electronic devices like

Structural evolution, photoelectron spectra and vibrational properties of anionic GdGen− (n = 5–18) nanoalloy clusters: a DFT insight

“…This phenomenon differs from Tb atom in TbSi n − compounds where 4f electrons of Tb prefer to take part in bonding via the 4f electrons jump into 5d orbitals. 52 (ii) Because there are no 4f electrons involved in bonding, the oxidation number of the Gd in GdGe n − compounds is three. (iii) For n = 5–9, the charge of Gd in GeGe n − is within +0.15 to +0.37 a.u.…”

Comment on “Realization of the Zn3+ oxidation state” by H. Fang, H. Banjade, Deepika and P. Jena, Nanoscale, 2021, 13, 14041–14048

“…Photoelectron spectroscopy is commonly used to specify the existence of elements and their oxidation states. 33,34 Here, theoretical X-ray photoelectron spectra are simulated based on Koopmans’ principle. 35,36 As shown in Fig.…”

Small chromium-doped silicon clusters CrSin: structures, IR spectra, charge effect, magnetism and chirality

“…For the location of the cationic CrSi n + and neutral CrSi n isomers, initial guess structures are generated by considering stable geometries of cationic, anionic, neutral metal and non-metal doped Si clusters reported in the literature. 3,9,31,32,34,39,40,59,62–69 Additionally, geometries of the pure Si clusters in different charge states taken from previous studies 31,34,37,42,44,70–73 are used as starting structures on which the Cr atom is added at various positions or an atom of the Si frame is replaced by a Cr atom. These structures are subsequently optimized in different multiplicities, from the singlet to the septet state for systems with an even number of electrons, and from the doublet to the octet state for systems with an odd number of electrons.…”