Computational analysis on native and extrinsic point defects in YAG using the metaGGA SCAN method

We report on the computational study of point defects in the well-known Y3Al5O12\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Y}_{3}\hbox {Al}_{5}\hbox {O}_{12}$$\end{document} (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 YAl\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$Y_{\mathrm{Al}}$$\end{document} antisites at Al octahedral position cannot be avoided whatever the synthesis atmosphere. As expected, VO\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V_{\mathrm{O}}$$\end{document} oxygen vacancies are easily formed under reducing atmospheres. Moreover, we have notably shown that the formal Ce3+/Ce4+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Ce}^{3+}/\hbox {Ce}^{4+}$$\end{document} charge transition level is getting closer to the experimental value for a Hubbard correction Ueff\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$U_{\mathrm{eff}}$$\end{document} of 5 eV. Last, the electron traps associated with the reduction of Cr3+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Cr}^{3+}$$\end{document} into Cr2+\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\hbox {Cr}^{2+}$$\end{document} species were identified near the conduction band.