Sm3+-Doped Bismuth(III) Oxosilicate (Bi4Si3O12:Sm3+): A Study of Crystal Structure and Mulliken Charges

In this paper, using the Materials Studio software (version 2020) and based on first-principles and density functional theory, the effects of Sm3+ doping at different ratios (1/12, 1/6, and 1/3) on the crystal structure and Mulliken charge distribution of bismuth silicate (Bi4Si3O12, BSO) were analyzed. The examination of the crystal framework and Mulliken charge allocation reveals that increasing levels of Sm3+ doping have the potential to warp the lattice’s symmetry and result in a decrease in electrical conductivity. With the rise in the concentration of Sm3+ doping, the Sm-O bond length shows a pattern of a rise at first and then a fall, demonstrating that electrons are shared, and reaches its minimum length with a doping proportion of 1/12. At the same time, when the doping concentration of Sm3+ rises, the Bi-O bond length becomes longer; it reaches its shortest length when the doping concentration is 1/12. This finding suggests that when a small quantity of Sm3+ is doped, especially when the doping concentration is 1/12, the covalent nature of the bonds between Sm-O and Bi-O atoms within the BSO crystal is strengthened.