First-Principles Investigation of Ferroelectricity in LaBGeO₅
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.
B. J. Demaske et al., "First-Principles Investigation of Ferroelectricity in LaBGeO₅," Journal of Physics: Condensed Matter, vol. 28, no. 16, Institute of Physics Publishing, May 2016.
The definitive version is available at https://doi.org/10.1088/0953-8984/28/16/165901
Center for High Performance Computing Research
Keywords and Phrases
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
International Standard Serial Number (ISSN)
Article - Journal
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01 May 2016