title: Simulating the Radio-Frequency Dielectric Response of Relaxor Ferroelectrics: Combination of Coarse-Grained Hamiltonians and Kinetic Monte Carlo Simulations.
abstract: The radio-frequency dielectric response of the lead-free Ba(Zr_{0.5}Ti_{0.5})O_{3} relaxor ferroelectric is simulated using a coarse-grained Hamiltonian. This concept, taken from real-space renormalization group theories, allows us to depict the collective behavior of correlated local modes gathered in blocks. Free-energy barriers for their thermally activated collective hopping are deduced from this ab initio-based approach, and used as input data for kinetic Monte Carlo simulations. The resulting numerical scheme allows us to simulate the dielectric response for external field frequencies ranging from kHz up to a few tens of MHz for the first time and to demonstrate, e.g., that local (electric or elastic) random fields lead to the dielectric relaxation in the radio-frequency range that has been observed in relaxors.
authors.affiliation: CEA, DAM, DIF, F-91297 Arpajon, France.
authors.forename: Grégory
authors.initials: G
authors.lastname: Geneste
authors.affiliation: Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA.
authors.forename: L
authors.initials: L
authors.lastname: Bellaiche
authors.affiliation: Laboratoire Structures, Propriétés et Modélisation des Solides, Université Paris Saclay, CentraleSupélec, CNRS (UMR 8580), Grande Voie des Vignes, 92295 Châtenay-Malabry, France.|LLB, CEA, CNRS, Université Paris-Saclay 91191 Gif-sur-Yvette, France.
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Kiat