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.
- Calculations,
- Electronic Properties,
- Ferroelectricity,
- Phase Transitions,
- Polarization,
- Temperature,
- Borogermanate,
- Ferroelectric Phasis,
- First-Principles Investigations,
- High Temperature Phase,
- Modern Theory of Polarization,
- Paraelectric Phasis,
- Spontaneous Polarizations,
- Vibrational Properties,
- Density Functional Theory,
- Density Functional Theory,
- Lanthanum Borogermanate
Available at: http://works.bepress.com/aleksandr-chernatynskiy/18/