Vibrational spectra and elastic piezoelectric and polarization properties of the {alpha}-SrB{sub 4}O{sub 7} crystal

The crystal lattice vibrational frequencies in the center of the Brillouin zone have been determined with the Raman spectroscopy method. The lattice vibrational frequencies, the phonon density of states, elastic and piezoelectric moduli, Born dynamic charges, and high-frequency dielectric constant have been calculated using the density functional method. All calculated quantities have been compared to the experimental data. A model of a nonpolar paraelectric phase for this compound, as well as a mechanism of the formation of domain in it, has been proposed. The polarization in the experimentally observed polar phase has been calculated.