Sr2IrO4 is the archetype of the spin-orbit Mott insulator, but the nature of the metallic states that may emerge from this type of insulator is still not very well known. We study with angle-resolved photoemission the insulator-to-metal transition observed in Sr2Ir1−xRhxO4 when Ir is substituted by Rh (0.02 < x < 0.35). The originality of the Rh doping is that Ir and Rh, which are formally isovalent, adopt different charge states, a rather unusual and inhomogeneous situation. We show that the evolution to the metallic state can be essentially understood as a shift of the Fermi level into the lower Hubbard band of Sr2IrO4. The Mott gap appears quite insensitive to the introduction of up to ∼20\% holes in this band. The metallic phase, which forms for x > 0.07, is not a Fermi liquid. It is characterized by the absence of quasiparticles, unrenormalized band dispersion compared to calculations and an ∼30-meV pseudo-gap on the entire Fermi surface.
@article{arxiv.1801.01459,
title = {Formation of an incoherent metallic state in Rh-doped Sr$_2$IrO$_4$},
author = {Alex Louat and Fabrice Bert and Lise Serrier-Garcia and François Bertran and Patrick Le Fèvre and Julien Rault and Véronique Brouet},
journal= {arXiv preprint arXiv:1801.01459},
year = {2018}
}