We investigate the bilayer Ruddlesden-Popper iridate Sr3Ir2O7 by temperature-dependent angle-resolved photoemission. We find a narrow-gap correlated insulator, with spectral features indicative of a polaronic ground state, strikingly similar to that observed previously for the parent compounds of the cuprate superconductors. We additionally observe similar behaviour for the single-layer cousin Sr2IrO4, indicating that strong electron-boson coupling dominates the low-energy excitations of this exotic family of materials, and providing a microscopic link between the insulating ground states of the seemingly-disparate 3d cuprates and 5d iridates.
@article{arxiv.1302.0433,
title = {Spectroscopic evidence for polaronic behaviour of the strong spin-orbit insulator Sr$_3$Ir$_2$O$_7$},
author = {P. D. C. King and T. Takayama and A. Tamai and E. Rozbicki and S. McKeown Walker and M. Shi and L. Patthey and R. G. Moore and D. Lu and K. M. Shen and H. Takagi and F. Baumberger},
journal= {arXiv preprint arXiv:1302.0433},
year = {2013}
}
Comments
6 pages, 4 figures. A high resolution version is available at http://www.st-andrews.ac.uk/~pdk6/pub_files/Ir327_cond_mat_HiRes.pdf