First principles studies of the Born effective charges and electronic dielectric tensors for the relaxor PMN (PbMg1/3Nb2/3O3)

Abstract

We report first principles density functional calculations of the Born effective charges and electronic dielectric tensors for the relaxor PMN (PbMg1/3Nb2/3O3). Visualization of the Born charge tensors as charge ellipsoids have provided microscopic insights on the factors governing piezoelectric enhancements with polarization rotation. Several 15 and 30-atom ferroelectric and antiferroelectric supercells of PMN involving 1:2 and 1:1 chemical ordering have been studied. A cascading set of ferroelectric phonon instabilities lead to several low symmetry monoclinic structures. We find a ground state with a 15-atom unit cell with 1:2 chemical ordering along [111] with a monoclinic C2 structure.

arXiv comment12 pages, 4 figures and 5 animations. Animations available from Elsevier Gateway, Computational Materials Science Site online publications. Computational Materials Science (In Press). Computational Materials Science (In Press)

References in corpus (4)

• Phonons and related properties of extended systems from density-functional perturbation theory
• Monoclinic and triclinic phases in higher-order Devonshire theory
• Lattice Dynamics in PMN
• Ab initio linear response and frozen phonons for the relaxor PMN (PbMg1/3Nb2/3O3)

Cited by in corpus (3)

• Origin of the large phonon band-gap in SrTiO3 and the vibrational signatures of ferroelectricity in ATiO3 perovskite: First principles lattice dynamics and inelastic neutron scattering of PbTiO3, BaTiO3 and SrTiO3
• First-Principles Calculation of Born Effective Charges and Spontaneous Polarization of Ferroelectric Bismuth Titanate
• First Principles Theories of Piezoelectric Materials