Figure 1. Atomic-resolution STEM characterization.

(a) HAADF-STEM images of the LaAlO₃/SrTiO₃ (001) interface. The left and right panels are magnified views of the interface observed from [100] and [1–10] zone axes, respectively. (b) HAADF-STEM images of the LaAlO₃/SrTiO₃ (110) interface. Left and right panels are magnified views of the interface observed from [001] and [1–10] directions, respectively. Both LaAlO₃ layers are continuous within the analysed region (of the order of 1 μm). The images in the central panels a and b have been Fourier filtered to reduce background noise. The positions of La and Sr are indicated by green and orange circles, whereas Al and Ti are shown in red and light green. Note that for both orientations the interfaces are atomically flat and that the (110) interface does not show any local (100) microfacet.