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.

Department(s)

Physics

Research Center/Lab(s)

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)

0953-8984

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Institute of Physics - IOP Publishing, All rights reserved.

Publication Date

01 May 2016

Link to Full Text

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