Antisite defects and traps in perovskiteYAlO3andLuAlO3: Density functional calculations

Abstract

Density functional calculations in supercells are used to investigate antisite point defects in $\mathrm{Y}\mathrm{Al}{\mathrm{O}}_{3}$ and $\mathrm{Lu}\mathrm{Al}{\mathrm{O}}_{3}$. It is found that antisites consisting of an Al on the Y(Lu) site and those consisting of an Y(Lu) on the Al site both have low energy with respect to binary oxide reservoirs. Defects containing Al on the $A$ site yield electron traps at $0.4--0.8\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ below the conduction band edge, while Y(Lu) ions on the Al site do not. Based on this it is suggested that growth conditions that avoid Al on the $A$ site may reduce the number of electron traps in these materials.