Sensitivity of electronic structure to crystal distortions in infinite layered LaNiO₂

Recent observations of unconventional superconductivity in thin films of LaNiO₂ (critical temperature T_c ~ 10 K) and in bulk single crystals of La₃Ni₂O₇ under pressure (T_c ~ 80 K) have cemented a long sought-after class of nickelates. Two important effects have come to light: the role of the 3d_z²-r² orbital and the Ni-O-Ni bond bending. In La₃Ni₂O₇, the emergence of superconductivity under pressure coincides with the metallization of the Ni 3d_z²-r²-like occupied band near the Gamma point. In LaNiO₂, superconductivity appears only in films for reasons not understood. Using neutron scattering on bulk samples and ab initio calculations, the role of the structure on the electronic properties was investigated. To gain more insights on the absence of superconductivity in bulk LaNiO₂ and its possible emergence under pressure, we perform a combination of experiments to probe the crystal structure and magnetic order, together with ab initio calculations of the electronic structure. Our results motivate future compression experiments on bulk LaNiO₂ to probe the emergence of superconductivity.