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- Ab Initio Calculations (1)
- Cauchy Relations (1)
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- Ferroelastic (1)
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- First-Principles Interionic Potentials (1)
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- Halide-Based Perovskites (1)
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- John R. Hardy Papers (1)
- Long-Range Electrostatic Potential (1)
- Longitudinal-and Transverse-Optic Mode Frequencies (1)
- Spherically Symmetric Charge Relaxation (1)
- Theoretchal Lattice-Dynamical Study (1)
- Triply Canted Halide Octahedra (1)
Articles 1 - 2 of 2
Full-Text Articles in Physics
First-Principles Study Of Structural Instabilities In Halide-Based Perovskites: Competition Between Ferroelectricity And Ferroelasticity, John W. Flocken, R. A. Guenther, John R. Hardy, L. L. Boyer
First-Principles Study Of Structural Instabilities In Halide-Based Perovskites: Competition Between Ferroelectricity And Ferroelasticity, John W. Flocken, R. A. Guenther, John R. Hardy, L. L. Boyer
Physics Faculty Publications
We have made a systematic theoretical survey of the competition between ferroelastic and ferroelectric instabilities in the family of halide-based perovskites of formula ABX3, where A is an alkali-metal ion, B is a Be, Mg, or Ca ion, and X is a halide ion. Initially we surveyed the whole series of such compounds, making a theoretical lattice-dynamical study using first-principles interionic potentials composed of a long-range pure Coulomb interaction between the spherically symmetric free ions, and a short-range component calculated by the Gordon-Kim approach from the overlapping free-ion charge densities. We then proceeded to examine in more detail three compounds, …
Beyond The Rigid-Ion Approximation With Spherically Symmetric Ions, L. L. Boyer, M. J. Mehl, J. L. Feldman, John R. Hardy, C. Y. Fong
Beyond The Rigid-Ion Approximation With Spherically Symmetric Ions, L. L. Boyer, M. J. Mehl, J. L. Feldman, John R. Hardy, C. Y. Fong
Physics Faculty Publications
Ab initio calculations show that a spherically symmetric charge relaxation of ions in a crystal, in response to the long-range electrostatic potential, is important for understanding the splitting between longitudinal- and transverse-optic-mode frequencies, and the violation of the Cauchy relations among elastic constants.