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Composition‐dependent intrinsic defect structures in pyroclore RE 2 B 2 O 7 ( RE = La, Nd, Gd; B = Sn, Hf, Zr)
Author(s) -
Yang Lan,
Wang Peiying,
Zhang Chengguan,
Liu Yuchen,
Cui Yuanyuan,
Zhang Liangmiao,
Liu Bin
Publication year - 2020
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.16705
Subject(s) - stoichiometry , pyrochlore , frenkel defect , crystallographic defect , vacancy defect , materials science , crystallography , oxygen , interstitial defect , oxygen atom , chemistry , doping , molecule , phase (matter) , optoelectronics , organic chemistry
Point defects are closely correlated with various properties of pyrochlore oxides and therefore play a key role on their engineering applications. Here, the native point defect complexes in RE 2 B 2 O 7 ( RE = La, Nd, Gd; B = Sn, Hf, Zr) under stoichiometric and nonstoichiometric compositions are studied by first‐principles calculations. The O Frenkel defect complex is predicted to be the predominant defect structure in stoichiometric zirconates and hafnates, whereas the cation antisite defect complex is the predominant one in stannates. In the case of B O 2 excess, the formation of the B‐RE antisite defect together with the RE vacancy and the oxygen interstitial is energetically favorable, whereas the RE‐B antisite defect together with the oxygen vacancy and the RE interstitial is preferable under the RE 2 O 3 excess environments. Additionally, the formation energies of the native defect complexes are greatly affected by the B ‐site and/or RE ‐site cations. The strategy on tailoring the intrinsic defect structures of these pyrochlore oxides is proposed. It is expected to guide the experiments on the defect‐related property optimization through stoichiometric and nonstoichiometric compositions, so as to meet the specific engineering requirements and promote their commercial applications.