Quasiparticle approach to the transport in infinite-layer nickelates

Abstract

The normal-state transport properties of superconducting infinite-layer nickelates are investigated within an interacting three-orbital model. It includes effective Ni-${d}_{{z}^{2}}$ and Ni-${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$ bands as well as the self-doping band degree of freedom. The thermopower, Hall coefficient, and optical conductivity are modeled within a quasiparticle approximation to the electronic states. Qualitative agreement in comparison to experimentally available Hall data is achieved, with notably a temperature-dependent sign change of the Hall coefficient for larger hole doping $x$. The Seebeck coefficient changes from negative to positive in a nontrivial way with $x$, but generally shows only a modest temperature dependence. The optical conductivity shows a pronounced Drude response and a prominent peak structure at higher frequencies due to interband transitions. While the quasiparticle picture is surely approximative to low-valence nickelates, it provides enlightening insights into the multiorbital nature of these challenging systems.