Single crystal growth and electronic structure of Rh-doped Sr₃Ir₂O₇

Ruddlesden-Popper iridate Sr₃Ir₂O₇ is a spin–orbit coupled Mott insulator. Hole doped Sr₃Ir₂O₇ provides an ideal platform to study the exotic quantum phenomena that occur near the metal–insulator transition (MIT) region. Rh substitution of Ir is an effective method to induce hole doping into Sr₃Ir₂O₇. However, the highest doping level reported in Sr₃(Ir_1−xRh_x)₂O₇ single crystals was only around 3%, which is far from the MIT region. In this paper, we report the successful growth of single crystals of Sr₃(Ir_1−xRh_x)₂O₇ with a doping level of ~ 9%. The samples have been fully characterized, demonstrating the high quality of the single crystals. Transport measurements have been carried out, confirming the tendency of MIT in these samples. The electronic structure has also been examined by angle-resolved photoemission spectroscopy (ARPES) measurements. Our results establish a platform to investigate the heavily hole doped Sr₃Ir₂O₇ compound, which also provide new insights into the MIT with hole doping in this material system.