Hi, I am doing some simulation and get a new structure and the stoichiometry is Al/O=1/1,not Al2O3. I searched almost all the journals, but still can not find any reference talking about a stoichiometry rather than Al/O=2/3. Is there any theoretical evidence saying that 2:3 is the only correct one? I mean, like Fe, there are FeO,Fe2O3 and Fe3O4,possiblly more. But why only Al2O3? If people have tried to find other stoichiometry, how was it?