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

Abstract

This article uses Materials Studio software, based on first-principles and density functional theory, to calculate and analyze the impact of Gd³⁺ doping on the crystal structure and the Mulliken charge distribution of bismuth silicate (Bi₄Si₃O₁₂, BSO). The virtual crystal approximation method is uesd to explore the influence of different doping ratios (1/12, 1/6, and 1/3) of Gd³⁺ on the BSO crystal. Through Mulliken charge analysis, it is found that a high proportion of Gd³⁺ doping can affect the symmetry of the crystal structure. As the doping ratio of Gd³⁺ 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 Gd³⁺ reaches 1/3, the length of the Gd-O bond reaches its minimum value. With an increase in the Gd³⁺ doping ratio, the Bi-O bond length first decreases and then increases, reaching its minimum value when the Gd³⁺ doping ratio is increases to 1/6. This indicates that when Gd³⁺ 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.