American Physical Society Acta Medica Okayama 2469-9950 96 4 2017 Evolution of the remnant Fermi-surface state in the lightly doped correlated spin-orbit insulator Sr2-xLaxIrO4 041106 EN Kensei Terashima Research Institute for Interdisciplinary Science, Okayama University M. Sunagawa Graduate School of Natural Sciences, Okayama University H. Fujiwara Graduate School of Natural Sciences, Okayama University T. Fukura M. Fujii Graduate School of Natural Sciences, Okayama University K. Okada Aoyama Gakuin University K. Horigane Research Institute for Interdisciplinary Science, Okayama University K. Kobayashi Research Institute for Interdisciplinary Science, Okayama University R. Horie Research Institute for Interdisciplinary Science, Okayama University J. Akimitsu Research Institute for Interdisciplinary Science, Okayama University E. Golias Helmholtz-Zentrum Berlin für Materialien und Energie D. Marchenko Helmholtz-Zentrum Berlin für Materialien und Energie A. Varykhalov Helmholtz-Zentrum Berlin für Materialien und Energie N. L. Saini Dipartimento di Fisica, Universitá di Roma gLa Sapienza T. Wakita Research Institute for Interdisciplinary Science, Okayama University Y. Muraoka Research Institute for Interdisciplinary Science, Okayama University T. Yokoya Research Institute for Interdisciplinary Science, Okayama University The electronic structure of the lightly electron-doped correlated spin-orbit insulator Sr2IrO4 has been studied by angle-resolved photoelectron spectroscopy. We have observed the coexistence of a lower Hubbard band and an in-gap band; the momentum dependence of the latter traces that of the band calculations without on-site Coulomb repulsion. The in-gap state remained anisotropically gapped in all observed momentum areas, forming a remnant Fermi-surface state, evolving towards the Fermi energy by carrier doping. These experimental results show a striking similarity with those observed in deeply underdoped cuprates, suggesting the common nature of the nodal liquid states observed in both compounds. No potential conflict of interest relevant to this article was reported.