One way to induce insulator to metal transitions in the spin-orbit Mott insulator Sr2IrO4 is to substitute iridium with transition metals (Ru, Rh). However, this creates intriguing inhomogeneous metallic states, which cannot be described by a simple doping effect. We detail the electronic structure of the Ru-doped case with angle-resolved photoemission and show that, contrary to Rh, it cannot be connected to the undoped case by a rigid shift. We further identify bands below EF coexisting with the metallic ones that we assign to non-bonding Ir sites. We rationalize the differences between Rh and Ru by a different hybridization with oxygen, which mediates the coupling to Ir and sensitively affects the effective doping. We argue that the spin-orbit coupling does not control neither the charge transfer nor the transition threshold.
@article{arxiv.2103.03056,
title = {Origin of the different electronic structure of Rh- and Ru-doped Sr2IrO4},
author = {Véronique Brouet and Paul Foulquier and Alex Louat and François Bertran and Patrick Le Fèvre and Julien E. Rault and Dorothée Colson},
journal= {arXiv preprint arXiv:2103.03056},
year = {2021}
}