R
Ronald E. Cohen
Researcher at Carnegie Institution for Science
Publications - 315
Citations - 18921
Ronald E. Cohen is an academic researcher from Carnegie Institution for Science. The author has contributed to research in topics: Phase transition & Perovskite (structure). The author has an hindex of 60, co-authored 311 publications receiving 17274 citations. Previous affiliations of Ronald E. Cohen include Smithsonian Astrophysical Observatory & National Institute of Standards and Technology.
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Origin of ferroelectricity in perovskite oxides
TL;DR: In this paper, the authors report results of electronic-structure calculations on two classic examples of ferroelectric perovskites, BaTiO3 and PbTiO2, and demonstrate that hybridization between the titanium 3d states and the oxygen 2p states is essential for ferroelectivity.
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Polarization rotation mechanism for ultrahigh electromechanical response in single-crystal piezoelectrics
Huaxiang Fu,Ronald E. Cohen +1 more
TL;DR: It is shown that a large piezoelectric response can be driven by polarization rotation induced by an external electric field, and the computations suggest how to design materials with better performance, and may stimulate further interest in the fundamental theory of dielectric systems in finite electric fields.
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More accurate generalized gradient approximation for solids
Zhigang Wu,Ronald E. Cohen +1 more
TL;DR: In this article, a non-empirical density functional generalized gradient approximation (GGA) was proposed for lattice constants, crystal structures, and metal surface energies, which is based on a diffuse radial cutoff for the exchange hole in real space, and the analytic gradient expansion of the exchange energy for small gradients.
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Origin of morphotropic phase boundaries in ferroelectrics
Muhtar Ahart,Maddury Somayazulu,Ronald E. Cohen,Panchapakesan Ganesh,Przemyslaw Dera,Ho-kwang Mao,Russell J. Hemley,Yang Ren,Peter Liermann,Zhigang Wu +9 more
TL;DR: This work shows that even a pure compound, in this case lead titanate, can display a morphotropic phase boundary under pressure, and finds that complex microstructures or compositions are not necessary to obtain strong piezoelectricity.
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Lattice dynamics and origin of ferroelectricity in BaTiO3: Linearized-augmented-plane-wave total-energy calculations.
Ronald E. Cohen,Henry Krakauer +1 more
TL;DR: Calcul des frequences de phonons et des vecteurs propres a partir des principes premiers pour les trois modes optiques F 1 u dans BaTiO 3 en utilisant la methode d'onde plane amelioree linearisee.