Fig. 1: Thickness dependence of the infinite layer structure.

a The XRD θ–2θ scan patterns of the Nd0.8Sr0.2NiO2 thin films with different thicknesses on SrTiO3 substrates. The intensity is vertically displaced for clarity. b The room-temperature c-axis lattice constants, c, as a function of thickness, as calculated from the (001) peak positions. The red dots represent the average c of the two sets of samples and the error bars represent the variance. c The HAADF-STEM image of the 10.1-nm Nd0.8Sr0.2NiO2 on SrTiO3 substrate.