2022
ACL
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W.Lafargue-Dit-Hauret, M.Allix, B.Viana, S.Jobic, C.Latouche, 'Computational analysis on native and extrinsic point defects in YAG using the metaGGA SCAN method', Theoretical Chemistry Accounts 141 58 (2022) doi:10.1007/s00214-022-02920-7
We report on the computational study of point defects in the well-known $$\hbox {Y}_{3}\hbox {Al}_{5}\hbox {O}_{12}$$(YAG) compound. DFT SCAN and SCAN+U calculations were used to access the electronic properties of the material taking into account both native defects and two substituting dopants, namely Ce and Cr. Defect formation enthalpies and defect concentrations were estimated for different synthesis conditions corresponding to extreme and intermediate limits of the stability diagram of YAG. We demonstrate that $$Y_{\mathrm{Al}}$$antisites at Al octahedral position cannot be avoided whatever the synthesis atmosphere. As expected, $$V_{\mathrm{O}}$$oxygen vacancies are easily formed under reducing atmospheres. Moreover, we have notably shown that the formal $$\hbox {Ce}^{3+}/\hbox {Ce}^{4+}$$charge transition level is getting closer to the experimental value for a Hubbard correction $$U_{\mathrm{eff}}$$of 5 eV. Last, the electron traps associated with the reduction of $$\hbox {Cr}^{3+}$$into $$\hbox {Cr}^{2+}$$species were identified near the conduction band.
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