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2018
ACL
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X.Yang, A.J.Fernández-Carrión, J.Wang, F.Porcher, F.Fayon, M.Allix, X.Kuang, 'Cooperative Mechanisms of Oxygen-Vacancy Stabilization and Migration in the Isolated Tetrahedral Network Scheelite Structure', Nat. Commun. 9 4484 (2018) doi:10.1038/s41467-018-06911-w
Tetrahedral units can transport oxide anions via interstitial or vacancy defects owing to their
great deformation and rotation flexibility. Compared with interstitial defects, vacancymediated
oxide-ion conduction in tetrahedra-based structures is more difficult and occurs
rarely. The isolated tetrahedral anion Scheelite structure has showed the advantage of
conducting oxygen interstitials but oxygen vacancies can hardly be introduced into Scheelite
to promote the oxide ion migration. Here we demonstrate that oxygen vacancies can be
stabilized in the BiVO4 Scheelite structure through Sr2+ for Bi3+ substitution, leading to
corner-sharing V2O7 tetrahedral dimers, and migrate via a cooperative mechanism involving
V2O7-dimer breaking and reforming assisted by synergic rotation and deformation of
neighboring VO4 tetrahedra. This finding reveals the ability of Scheelite structure to transport
oxide ion through vacancies or interstitials, emphasizing the possibility to develop oxide-ion
conductors with parallel vacancy and interstitial doping strategies within the same
tetrahedra-based structure type.
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