title: First-principles investigation of ferroelectricity in LaBGeO5.
abstract: Density functional theory calculations are performed to characterize the structural, electronic and vibrational properties of both the low-temperature ferroelectric and high-temperature paraelectric phases of LaBGeO5. Phonon dispersion calculations for the high-temperature phase reveal an unstable mode whose zone-center eigenvector corresponds to a rigid rotation of the BO4 tetrahedra, in agreement with previous calculations based on a short-range model potential. A possible switching path between two symmetry-equivalent ferroelectric phases that goes through the high-temperature paraelectric phase is identified and used to calculate the spontaneous polarization. The theoretical value for the spontaneous polarization calculated using the modern theory of polarization is 4.9 μC cm(-2) for the PBEsol  +  U functional, which lies within the experimental range.
authors.affiliation: Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Demaske
authors.forename: A
authors.initials: A
authors.lastname: Chernatynskiy
authors.forename: S R
authors.initials: SR
authors.lastname: Phillpot