Extended Data Fig. 3: Details of the large-area O-K edge EELS map.
From: Visualization of oxygen vacancies and self-doped ligand holes in La3Ni2O7−δ
a, STEM-HAADF image displaying the sample geometry near the region we have performed EELS mapping. b, The same prepeak map as Fig. 3e. The black, blue, and red rectangles select representative regions with strong, medium, and weak prepeak. c, Average O-K EELS for the previously selected regions with the same color. The variation in prepeak intensity is considerable from our EELS results.