Issue 43, 2015

A new perspective on the process of intrinsic point defects in α-Al2O3

Abstract

First-principles plane-wave pseudopotential calculations have been performed to study the charge states and energetics of intrinsic point defects as vacancies, interstitials and antisite atoms in α-Al2O3, and thus a new perspective on the process of intrinsic point defects has been proposed. Considering the various charge states for each intrinsic point defects, VAl3−, V0O, Ali3+, Oi2−, AlO3+, and OAl3−, not all in their fully ionized states are found to be most stable and in pure Al2O3. From the formation energies of individual point defects, the antisite atom OAl will be readily formed in α-Al2O3 in an O-rich environment. By combination of charge states and formation energies, the defect types of Schottky, Al Frenkel and antisite pairs formed are found to be dependent on the O condition, and the most stable Schottky defect type is not the commonly considered {3VO2+:2VAl3−}. There are two types of possible O Frenkel defects under both O conditions, yet the most stable defect is {Oi1+:VO1−} rather than the commonly believed {Oi2+:VO2−}. The bizarre configuration and the charge state of Schottky and Frenkel defects predicated in this work provide a new perspective on the process of intrinsic point defects in α-Al2O3.

Graphical abstract: A new perspective on the process of intrinsic point defects in α-Al2O3

Article information

Article type
Paper
Submitted
15 Aug 2015
Accepted
04 Oct 2015
First published
06 Oct 2015

Phys. Chem. Chem. Phys., 2015,17, 29134-29141

Author version available

A new perspective on the process of intrinsic point defects in α-Al2O3

X. Xiang, G. Zhang, X. Wang, T. Tang and Y. Shi, Phys. Chem. Chem. Phys., 2015, 17, 29134 DOI: 10.1039/C5CP04867B

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