Single crystal growth and electronic structure of Fe-doped Sr₃Ir₂O₇

Abstract Metal–insulator transition (MIT) in perovskite iridium oxides Sr n +1 Ir n O 3 n +1 represents one of the most attractive phenomena exemplifying the cooperation of Coulomb interaction and spin–orbit coupling (SOC). MIT takes place when Sr n +1 Ir n O 3 n +1 ( n = 1, 2) is doped with carriers. While electron-doped Sr n +1 Ir n O 3 n +1 ( n = 1, 2) systems have been extensively investigated, hole-doped samples are still limited. Here, we report the first growth of Fe-doped (hole-doped) Sr 3 Ir 2 O 7 single crystals [Sr 3 (Ir 1− x Fe x ) 2 O 7 ] with the doping level 0.1 ≤ x ≤ 0.28. An MIT behavior is observed at the doping level of x ∼ 0.16 from resistivity measurements. Electronic structures of Fe-doped Sr 3 Ir 2 O 7 have been revealed by angle-resolved photoemission spectroscopy (ARPES) measurements. The evident energy shift of the band structure indicates higher hole-doping level as compared with Rh-doped Sr 3 Ir 2 O 7 . Our results demonstrate that Fe doping serves as an effective approach for heavily hole doping in Sr 3 Ir 2 O 7 , thereby offering a powerful strategy to modulate MIT in this material system.