The perovskite iridates ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ and ${\mathrm{Sr}}_3{\mathrm{Ir}}_2{\mathrm{O}}_7$ represent novel systems for exploring the electronic structure that is characteristic of Mott insulators upon carrier doping. Using angle-resolved photoemission spectroscopy (ARPES), we reveal a previously unobserved suppression of spectral weight near the Fermi level in the conduction band of very lightly electron-doped ${\left({\mathrm{Sr}}_{1-x}{\mathrm{La}}_x\right)}_3{\mathrm{Ir}}_2{\mathrm{O}}_7$ followed by a loss of coherence at high temperature. The doping and temperature dependence of this suppression suggests a correspondence with the antiferromagnetic Mott state. These results connect ${\left({\mathrm{Sr}}_{1-x}{\mathrm{La}}_x\right)}_3{\mathrm{Ir}}_2{\mathrm{O}}_7$ to other doped Mott insulators and add to the growing evidence of universal physics in these systems.

• Received 3 November 2016
• Revised 21 March 2017

DOI:https://doi.org/10.1103/PhysRevB.95.235151