Goodge, et al. 
“Reconstructing the polar interface of infinite-layer nickelate thin films”

Figure 3

npz structure: 
        layers = list of arrays for EELS of each atomic layer: each list entry is structured as [bgsub_Ti-L2,3, bgsub_O-K, layer_number])        STO_Ti_ref = background subtracted Ti-L2,3 edge of bulk-like SrTiO3
        STO_O_ref = background subtracted O-K edge of bulk-like SrTiO3, 
        NNO_O_ref = background subtracted O-K edge of bulk-like NdNiO2,
        energy = calibrated energy axis for all EELS spectra)