Doping at the Sr site in ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ is predicted to be a possible route to high-temperature superconductivity, which has not yet been experimentally achieved. We have made a comprehensive investigation on the interplay among the Ir-O-Ir bond angle, carrier density, and magnetic and transport properties of rare-earth-doped ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ by choosing Pr and Ce as the dopants. We find that compared with Pr doping, Ce doping introduces more effective charge carriers into the ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ matrix, leading to a more rapid suppression of its magnetic ordering. A metallic-like behavior has been observed in heavily Ce-doped samples. The evolutions of magnetic and transport behaviors are found to be less relevant to the distorted Ir-O-Ir bond angle. The present results suggest that the charge carrier density could be a crucial factor in determining the physical properties of rare-earth-doped ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ compounds.

• Received 16 June 2020
• Revised 25 August 2020
• Accepted 29 October 2020

DOI:https://doi.org/10.1103/PhysRevMaterials.4.115001