Fig. 1: STEM investigations of an ETO:MgO VAN film.

a Z-contrast HAADF-STEM image of the VAN film in cross-sectional orientation, projected along the [010] zone axis. b Atomically resolved STEM-EELS elemental maps of a single nanopillar, corresponding to the rectangle region in (a). Scale bar: 10 nm. c HAADF-STEM image of the VAN film in plan-view orientation, showing MgO nanopillars embedded in an ETO matrix. d–h Atomically resolved STEM-EELS elemental maps of a single nanopillar, corresponding to the rectangle region in (c). Scale bar: 2 nm. i EELS signal intensity profiles across the ETO/MgO interfaces extracted along the white arrow direction in (h).