Lattice dynamics of FeBO3 and GaBO3 crystals: Ab initio calculation

Within the framework of an unified ab initio approach the crystal structure, the effect of hydrostatic pressure on the crystal structure, and the phonon spectra of crystals FeBO3 and GaBO3 were investigated. Also, an analysis of the displacement vectors has been obtained from the ab initio calculation, which made it possible to estimate the degree of the ion displacements in each vibrational mode. Calculations were carried out within the framework of MO LCAO approach and the density functional theory, by using PBE0 hybrid functional which takes into account both the local and nonlocal (in the Hartree–Fock formalism) exchange. The calculations were performed with CRYSTAL14 software designed to simulate periodic structures. The results of the performed calculations suggest new features of the title crystals under pressure and new vibrational properties.