Computer modelling of Bi12SiO20 and Bi4Si3O12: Intrinsic defects and rare earth ion incorporation

Defect properties of Bi12SiO12 and Bi4Si3O12 compounds were investigated using atomistic computer modelling techniques based on energy minimisation. Interatomic potentials obtained by empirical fitting reproduce the lattice parameters for both materials and the available elastic and dielectric constants with reasonable accuracy. The relative stability of the phases and the intrinsic defects of both phases are predicted. A new methodology is used for calculating solution energies for rare earth doping which takes doping concentration into account