Doping-dependent character and possible magnetic ordering of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>NdNiO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>
Frank Lechermann
Abstract
The novel nickelate superconductors of infinite-layer type feature challenging electronic pecularities in the normal-state phase diagram with doping. Distinct many-body behavior and different dispersion regimes of the entangled ${\mathrm{Ni}\text{\ensuremath{-}}{d}_{{z}^{2}}$, Ni-${d}_{{x}^{2}\ensuremath{-}{y}^{2}}}$ orbital sector give rise to highly rich physics, which is here studied for the case of the $\mathrm{Nd}\mathrm{Ni}{\mathrm{O}}_{2}$ system. An analysis based on advanced realistic dynamical mean-field theory unveils that the superconducting hole-doped region is the meeting place of a (self-)doped Mott insulator from the underdoped side, and a bad Hund metal from the overdoped side. Fermi-level crossing of the Ni-${d}_{{z}^{2}}$ flat-band ties both regimes together to form a singular arena for unconventional superconductivity. We furthermore shed light on the intriguing problem of elusive magnetism in infinite-layer nickelates. Antiferromagnetic (AFM) order with small Ni moments is shown to be a vital competitor at low temperature. At stoichiometry, C-AFM order with ferromagnetic spin-alignment along the $c$-axis benefits from a conceivable coexistence with Kondo(-lattice) screening.