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The ReaxFF polarizable reactive force fields for molecular dynamics simulation of ferroelectrics

Goddard, William A., III and Zhang, Qingsong and Uludogan, Mustafa and Strachan, Alejandro and Çağin, Tahir (2002) The ReaxFF polarizable reactive force fields for molecular dynamics simulation of ferroelectrics. In: Fundamental physics of ferroelectrics 2002. AIP Conference Proceedings. No.626. American Institute of Physics , Melville, N.Y., pp. 45-55. ISBN 0-7354-0079-2 . http://resolver.caltech.edu/CaltechAUTHORS:20111026-130045474

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Abstract

We use ab initio Quantum Mechanical (QM) calculations to derive a force field that accurately describes the atomic interactions in BaTiO3 allowing, via Molecular Dynamics (MD), the simulation of thousands of atoms. A key feature of the force field (denoted ReaxFF) is that charge transfer and atomic polarization are treated self-consistently. The charge on each atom is separated into a core, described as a Gaussian distribution with fixed total charge (e.g. +4 for Ti), and a valence charge, also described as a Gaussian distribution. The valence charges can flow in response to its environment as described via Charge Equilibration (QEq). The restoring force between a core and its valence electrons is given be the electrostatic interaction between the two charge distributions. Thus each atom has four universal parameters describing the electrostatics which are determined once from fitting to the QM charge distributions on a representative set of finite clusters. The nonelectrostatic interactions (Pauli repulsion, dispersion) are described with a Morse potential, leading to 3 additional universal parameters for each pair of atoms. We optimized the Morse parameters to reproduce the zero temperature Equation of State (energy- and pressure-volume curves) obtained using QM methods of cubic and tetragonal BaTiO_3 over a wide pressure range. We then use the ReaxFF with MD to study thermal properties of BaTiO_3, in particular the cubic to tetragonal phase transition. Our MD simulations indicate that the transition temperature obtained using ReaxFF is in good agreement with experiment.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1063/1.1499551 DOIArticle
http://link.aip.org/link/?APCPCS/626/45/1PublisherArticle
ORCID:
AuthorORCID
Goddard, William A., III0000-0003-0097-5716
Çağin, Tahir0000-0002-3665-0932
Additional Information:© 2002 American Institute of Physics. Issue Date: 17 August 2002. The work was supported the ARO-MURI project "Engineering Microstructural Complexity in Ferroelectric Devices" (Prog. Manager: John Prater). Additional support was provided from the Center for Science and Engineering of Materials, which is funded by a NSF MRSEC. Also some support was provided by the DOE ASCI ASAP at Caltech. This work was carried out in the Materials and Process Simulation Center (MSC) at Caltech whose facilities are also funded by NIH, NSF (CHE and MRI), ARO MURI, ChevronTexaco, MMM, Seiko-Epson, Kellogg's, Avery Dennison, Beckman Institute, Asahi Kasei, and Nippon Steel.
Funders:
Funding AgencyGrant Number
Army Research Office (ARO)UNSPECIFIED
NSFUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Subject Keywords:molecular dynamics method, potential energy functions, equations of state, crystal chemistry, crystal structure, solid-state phase transformations, ferroelectric materials, barium compounds, titanium compounds
Classification Code:PACS: 63.10.+a; 64.30.+t; 61.50.Ks; 77.84.Dy
Record Number:CaltechAUTHORS:20111026-130045474
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20111026-130045474
Official Citation:The ReaxFF Polarizable Reactive Force Fields for Molecular Dynamics Simulation of Ferroelectrics William A. Goddard III, Qingsong Zhang, Mustafa Uludogan, Alejandro Strachan, and Tahir Cagin, AIP Conf. Proc. 626, 45 (2002), DOI:10.1063/1.1499551
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:27453
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:26 Oct 2011 21:21
Last Modified:20 Apr 2017 18:38

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