Lattice dynamics in improper ferroelectric YGaO3

The structural phase transition P6₃/mmc → P6₃cm in hexagonal YGaO₃ crystal is studied by first-principles methods. From lattice dynamics calculations it was obtained that the mechanism of transition into polar phase is similar to the one in isostructural YMnO₃ crystal. As a result of calculations the improper ferroelectricity and electrical polarization were revealed in YGaO₃.