Fig. 1: Strain-tuning for ligand field control of La3Ni2O7 thin films.
From: Strain-tuning for superconductivity in La3Ni2O7 thin films
a Crystal structure of bilayer nickelates La3Ni2O7 and the energy diagram of Ni eg orbitals. b Lattice constants of SrTiO3, NdGaO3, and LaAlO3 substrates. c HAADF-STEM cross-sectional image of a La3Ni2O7 thin film grown on NdGaO3 taken along the La3Ni2O7 [110] axis (scale bar 5 nm). Arrow represents the interface. d Reciprocal space maps of La3Ni2O7 (1117)/ LaAlO3 (103) (left) and La3Ni2O7 (1117)/NdGaO3 (103)pc (right). e Experimentally obtained lattice constants of La3Ni2O7 films grown on SrTiO3, NdGaO3, and LaAlO3 substrates. Bulk values are shown in open diamonds1. f Calculations of a-axis length of La3Ni2O7 films on NdGaO3 and LaAlO3 by assumption of bulk compression ratio. Bulk values are plotted with open diamonds1.
