Extended Data Fig. 6: DFT-calculated structural evolutions under pressure.
From: Interstitial oxygen order and its competition with superconductivity in La2PrNi2O7+δ
a-b, Schematics for the relaxed structures (a), lattice constants and Ni-O-Ni bond angles (b) as a function of the hydrostatic pressure for AG phase La2PrNi2O7. The structural phase transition from Amam to I4/mmm is found around 15 GPa. c-d, Schematics for the relaxed structures (c), lattice constants and Ni-O-Ni bond angles (d) as a function of the hydrostatic pressure for HPO phase La2PrNi2O7.23. No structural phase transition is observed up to 100 GPa. An effective Hubbard U = 3.5 eV was applied when optimizing the crystal structures.
