title: Activation volume tensor for oxygen-vacancy migration in strained CeO2 electrolytes.
abstract: We examine the effect of mechanical strain on the migration of oxygen vacancies in fluorite-structured ceria by means of density functional theory calculations. Different strain states (uniaxial, biaxial and isotropic) and strain magnitudes (up to ± 7%) are considered. From the calculations we extract the complete activation volume tensor for oxygen-vacancy migration in CeO(2), that is, all diagonal ΔV(mig,kk) and off-diagonal ΔV(mig,kl) tensor elements. These individual tensor elements are found, crucially, to be independent of strain state; they do, however, depend on stress (ΔV(mig,kk)) or effective pressure (ΔV(mig,kl)). Armed with knowledge of all tensor elements we predict strain states for which oxygen-ion transport in ceria is maximized. In general, with our approach the effect of an arbitrary strain state on the migration barrier for mass transport in a solid can be calculated quantitatively.
authors.affiliation: Institute of Physical Chemistry, RWTH Aachen University and JARA-FIT, 52056 Aachen, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Hinterberg
authors.affiliation: Institute of Physical Chemistry, RWTH Aachen University and JARA-FIT, 52056 Aachen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Zacherle
authors.affiliation: Institute of Physical Chemistry, RWTH Aachen University and JARA-FIT, 52056 Aachen, Germany.
authors.forename: R A
authors.initials: RA
authors.lastname: De Souza