title: Photostriction in Ferroelectrics from Density Functional Theory.
abstract: An ab initio procedure allowing the computation of the deformation of ferroelectric-based materials under light is presented. This numerical scheme consists in structurally relaxing the system under the constraint of a fixed n_{e} concentration of electrons photoexcited into a specific conduction band edge state from a chosen valence band state, via the use of a constrained density functional theory method. The resulting change in lattice constant along a selected crystallographic direction is then calculated for a reasonable estimate of n_{e}. This method is applied to bulk multiferroic BiFeO_{3} and predicts a photostriction effect of the same order of magnitude than the ones recently observed. A strong dependence of photostrictive response on both the reached conduction state and the crystallographic direction (along which this effect is determined) is also revealed. Furthermore, analysis of the results demonstrates that the photostriction mechanism mostly originates from the screening of the spontaneous polarization by the photoexcited electrons in combination with the inverse piezoelectric effect.
authors.affiliation: Laboratoire Structures, Propriétés et Modélisation des Solides, CentraleSupélec, CNRS UMR8580, Université Paris-Saclay, 92290 Châtenay-Malabry, France.|Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: Charles
authors.initials: C
authors.lastname: Paillard
authors.affiliation: Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA.|Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.affiliation: Laboratoire Structures, Propriétés et Modélisation des Solides, CentraleSupélec, CNRS UMR8580, Université Paris-Saclay, 92290 Châtenay-Malabry, France.
authors.forename: Brahim
authors.initials: B
authors.lastname: Dkhil
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon France.
authors.forename: Grégory
authors.initials: G
authors.lastname: Geneste
authors.affiliation: Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA.|Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: L
authors.initials: L
authors.lastname: Bellaiche