Dynamical atomic charges: The case ofcompounds
- 1 September 1998
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 58 (10), 6224-6240
- https://doi.org/10.1103/physrevb.58.6224
Abstract
Based on recent first-principles computations in perovskite compounds, especially we examine the significance of the Born effective charge concept and contrast it with other atomic charge definitions, either static (Mulliken, Bader, etc.) or dynamical (Callen, Szigeti, etc.). It is shown that static and dynamical charges are not driven by the same underlying parameters. A unified treatment of dynamical charges in periodic solids and large clusters is proposed. The origin of the difference between static and dynamical charges is discussed in terms of local polarizability and delocalized transfers of charge: local models succeed in reproducing anomalous effective charges thanks to large atomic polarizabilities but, in compounds, ab initio calculations favor the physical picture based upon transfer of charges. Various results concerning barium and strontium titanates are presented. The origin of anomalous Born effective charges is discussed thanks to a band-by-band decomposition which allows us to identify the displacement of the Wannier center of separated bands induced by an atomic displacement. The sensitivity of the Born effective charges to microscopic and macroscopic strains is examined. Finally, we estimate the spontaneous polarization in the four phases of barium titanate.
Keywords
This publication has 79 references indexed in Scilit:
- Non-nominal value of the dynamical effective charge in alkaline-earth oxidesPhysical Review B, 1997
- Application of a Kohn-Sham-like formulation of the self-consistent atomic deformation modelFerroelectrics, 1997
- Ab initiolinear response study of SrTiO3Ferroelectrics, 1997
- Density-Polarization Functional Theory of the Response of a Periodic Insulating Solid to an Electric FieldPhysical Review Letters, 1995
- Pseudopotential methods in condensed matter applicationsComputer Physics Reports, 1989
- Shell model and single-particle ion potentials in BaTiO3crystalFerroelectrics, 1988
- Soft modes and the structure, spontaneous polarization and Curie constants of perovskite ferroelectrics: tetragonal potassium niobateJournal of Physics C: Solid State Physics, 1973
- Infra-red intensities in CH2F2, CH2Cl2 and CF2Cl2Spectrochimica Acta, 1966
- ‘Effective’ Ionic Charge in CrystalsNature, 1961
- Electrical Behavior of Barium Titanatge Single Crystals at Low TemperaturesPhysical Review B, 1955