Competing stripe phases in the undoped infinite-layer nickelate

Recent discovery of superconductivity in the nickelates has ignited renewed theoretical and experimental interest in the role of electronic correlations in their properties. In this talk, based on in-depth first-principles and random phase approximation modeling, I will show that the parent (undoped) compound of the nickelate family, LaNiO₂, hosts competing low energy phases, unlike the undoped cuprates but similar to the case of the doped cuprates. In particular, we find charge density wave vectors in agreement with experimental findings. We also show that flat bands near the Fermi level, stemming from the Ni-3dz² orbitals, persist across the various predicted low-energy phases of the nickelates.  Our study gives insight into the microscopic origin of electronic inhomogeneity and the lack of long-range order in nickelates.