Numerical study of the structural and vibrational properties of amorphous Ta₂O₅ and TiO₂-doped Ta₂O₅ Available to Purchase

Using classical molecular dynamics simulations, we synthesized amorphous Ta₂O₅ and amorphous TiO₂-doped Ta₂O₅. We show that Ta₂O₅ is composed primarily of six-folded Ta atoms forming octahedra that are either organized in chain-like structures or share edges or faces. When Ta₂O₅ is doped with TiO₂, Ti atoms form equally five- and six-folded polyhedra that perturb but do not break the network structure of the glass. Performing a vibrational eigenmode analysis and projecting the eigenmodes on the rocking, stretching, and bending motions of the Ta-2O and Ta-3O bonds, we provide an atomic-scale analysis that substantiates the interpretations of Raman spectra of amorphous Ta₂O₅. This eigenmode analysis also reveals the key role played by Ti atoms in the 5 to 12 THz range.