Phase Diagram and Superconducting Dome of Infinite-Layer Nd1−xSrxNiO2 Thin Films

Abstract

Infinite-layer ${\mathrm{Nd}}_{1-x}{\mathrm{Sr}}_x{\mathrm{NiO}}_2$ thin films with Sr doping level $x$ from 0.08 to 0.3 are synthesized and investigated. We find a superconducting dome $x$ between 0.12 and 0.235 accompanied by a weakly insulating behavior in both under- and overdoped regimes. The dome is akin to that in the electron-doped 214-type and infinite-layer cuprate superconductors. For $x\ge 0.18$, the normal state Hall coefficient ($R_H$) changes the sign from negative to positive as the temperature decreases. The temperature of the sign changes decreases monotonically with decreasing $x$ from the overdoped side and approaches the superconducting dome at the midpoint, suggesting a reconstruction of the Fermi surface with the dopant concentration across the dome.