Mapping band alignment across complex oxide heterointerfaces

In this study, direct observation of the evolution of electronic structures across complex oxide interfaces has been revealed in the LaAlO ₃/SrTiO₃ model system using cross-sectional scanning tunneling microscopy and spectroscopy. The conduction and valence band structures across the LaAlO₃/SrTiO₃ interface are spatially resolved at the atomic level by measuring the local density of states. This study directly maps out the electronic reconstructions and a built-in electric field in the polar LaAlO₃ layer. Results also clearly reveal the band bending and the notched band structure in the SrTiO₃ adjacent to the interface.