Correlations tune the electronic structure of pentalayer nickelates into the superconducting regime
Paul Worm, Liang Si, Motoharu Kitatani, Ryotaro Arita, Jan M. Tomczak, Karsten Held
Abstract
Motivated by the recent discovery of superconductivity in the pentalayer nickelate ${\mathrm{Nd}}_{6}{\mathrm{Ni}}_{5}{\mathrm{O}}_{12}$ [G. A. Pan et al., Nat. Mater. 21, 160 (2022)], we calculate its electronic structure and superconducting critical temperature. We find that electronic correlations are essential for pushing ${\mathrm{Nd}}_{6}{\mathrm{Ni}}_{5}{\mathrm{O}}_{12}$ into the superconducting doping range as they shift the electron pockets above the Fermi energy. As a consequence, ${\mathrm{Nd}}_{6}{\mathrm{Ni}}_{5}{\mathrm{O}}_{12}$ can be described with a single ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ orbital per Ni. We predict the pentalayer to be overdoped; further improvements in ${T}_{c}$ can be expected for a few additional layers. Instead, for the bilayer nickelate ${\mathrm{Nd}}_{3}{\mathrm{Ni}}_{2}{\mathrm{O}}_{6}$ we find correlations to drive the system into a three-orbital regime also involving the Ni ${d}_{xz,yz}$ states. We suggest, however, that single-orbital physics with optimal doping can be restored by substituting 60% of the trivalent Nd or La by tetravalent Zr.