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