Sr2IrO4 was predicted to be an unconventional superconductor upon carrier doping since it highly resembles the high-temperature cuprates. Here, to understand carrier doping effect on spin-orbit coupled Mott insulator Sr2IrO4, the electronic structure and local structure distortion for Sr2-xLaxIrO4 system have been investigated by x-ray absorption spectroscopy (XAS). By comparing the intensity of white-line features at the Ir L2,3 absorption edges, we observe remarkably large branching ratios in La-doped compounds, greater than that of the parent material Sr2IrO4, suggesting a strong spin-orbit interaction (SOI) for Sr2IrO4-based system. Moreover, extended x-ray absorption fine structure (EXAFS) spectra demonstrate more regular IrO6 octahedra, i.e. the weakened crystal electric field (CEF) versus La-doping. By theoretical calculations, the synergistic effect of regular IrO6 octahedra and electron doping is established, which accounts for the transition from a Mott insulator to a conductive state in Sr2-xLaxIrO4-based system.
@article{arxiv.1610.09839,
title = {La-doping effect on spin-orbit coupled Sr2IrO4 probed by x-ray absorption spectroscopy},
author = {Jie Cheng and Xuanyong Sun and Shengli Liu and Bin Li and Haiyun Wang and Peng Dong and Yu Wang and Wei Xu},
journal= {arXiv preprint arXiv:1610.09839},
year = {2017}
}
Comments
14 pages, 6 figures. arXiv admin note: text overlap with arXiv:1610.09817