Electronically coupled complementary interfaces between perovskite band insulators.

摘要: Perovskite oxides exhibit a plethora of exceptional properties, providing the basis for novel concepts of oxide-electronic devices. The interest in these materials is even extended by remarkable characteristics of their interfaces. Studies on single epitaxial connections between wide-bandgap insulators LaAlO3 and SrTiO3 have revealed them to be either high-mobility electron conductors or insulating, depending atomic stacking sequences. For device applications, as well as for basic understanding interface conduction mechanism, it is important investigate electronic coupling closely spaced complementary interfaces. Here we report successful realization such coupled interfaces SrTiO3–LaAlO3 thin-film multilayer structures. We found critical separation distance six perovskite unit cell layers, corresponding approximately 23 A˚ , below which decrease conductivity and carrier density occurs. Interestingly, high carrier mobilities characterizing separate conducting interfaces are bemaintained coupled structures down subnanometre spacing.