Transport phase diagram and anomalous metallicity in superconducting infinite-layer nickelates

Despite obvious similarities in their electronic and crystallographic structures, it remains unclear whether the interactions that shape the normal and superconducting (SC) state properties of high-T_c cuprates and infinite-layer nickelates (ILNs) have the same origin. This question has been brought into sharper focus with recent studies on ILNs of improved crystallinity that reveal a SC dome of comparable extent and similar transport properties above T_c as the hole-doped cuprates. The evolution of these properties in the magnetic field-induced normal state, however, has yet to be determined. Here, we examine the magnetotransport properties of new-generation Nd_1−xSr_xNiO₂ films in the T → 0 limit across the phase diagram in fields up to 54 T. This extensive study reveals that the limiting low-T form of the normal-state resistivity in ILNs exhibits non-Fermi-liquid behaviour over an extended doping range inside the SC dome, rather than at a singular quantum critical point. While there are clear differences in the charge dynamics of ILNs and cuprates, most notably in the magnetoresistance, our findings reveal that both systems exhibit anomalous metallicity characteristic of a quantum critical phase.