Novel two-dimensional perovskites

Using the example of rare earth titanium oxides, a new route for tailoring superlattices in bulk oxides will be discussed. Starting with well-known ABO(3) compounds, series of artificial structures can be created in a systematic way by oxygen intercalation, i.e. by an ordered incorporation of excess oxygen to form ABO(3+y) compositions. This intercalation process slices the three-dimensional ABO(3) structure into subunits of various thickness, each representing a defined oxygen composition. These basic units can be combined in multiple ways to form new superlattices whose physical character varies between semiconductor and ferroelectric insulator. These variations can be achieved without changing the chemical character of the compound, in contrast to the usual procedure of extrinsic doping, which creates disorder.