Electronic defects in LaAlO3

We present calculations of the energy levels of the oxygen vacancy, the AlLa antisite and the oxygen interstitial defects in LaAlO3 using density functional methods that do not need an empirical bandgap correction. The levels are aligned to those of the Si channel using the known band offsets. The oxygen vacancy gives an energy level near the LaAlO3 conduction band and above the Si gap. It is identified as the main electron trap and a cause of instability. There is only one vacancy level in the gap, because the higher second level lies within the La conduction band. The AlLa antisite gives a state near midgap, neutral when empty, which would be an important trap, with no counterpart in HfO2.