Crystal structure and Mulliken charge analysis of Gd3+doped bismuth silicate

This article uses Materials Studio software, based on first-principles and density functional theory, to calculate and analyze the impact of Gd 3+ doping on the crystal structure and the Mulliken charge distribution of bismuth silicate (Bi 4 Si 3 O 12 , BSO). The virtual crystal approximation method is uesd to explore the influence of different doping ratios (1/12, 1/6, and 1/3) of Gd 3+ on the BSO crystal. Through Mulliken charge analysis, it is found that a high proportion of Gd 3+ doping can affect the symmetry of the crystal structure. As the doping ratio of Gd 3+ increases,the length of the Gd-O bond exhibits a trend of first increasing and then decreasing, showing covalent bond properties, and when the doping ratio of Gd 3+ reaches 1/3, the length of the Gd-O bond reaches its minimum value. With an increase in the Gd 3+ doping ratio, the Bi-O bond length first decreases and then increases, reaching its minimum value when the Gd 3+ doping ratio is increases to 1/6. This indicates that when Gd 3+ is doped into the BSO crystal, the covalency between the Gd-O atoms is more significant at a doping ratio of 1/3, and the covalency between the Bi-O atoms is more significant at a doping ratio of 1/6. This article utilizes the Materials Studio software to construct a crystal model based on an expanded 3×3×3 bismuth silicate (Bi 4 Si 3 O 12 , BSO) supercell, employing the method of atomic substitution for doping. As shown in the figure, Bi atoms are replaced by Gd atoms at different ratios of 1/12 (a), 1/6 (b), and 1/3 (c), and the study analyzes the impact of Gd 3+ doping on the BSO crystal structure and Mulliken charge distribution.