文章基本信息

标题：Atomically resolved spectroscopic study of Sr₂IrO₄: Experiment and theory
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作者：Qing Li ; Guixin Cao ; Satoshi Okamoto 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2013
卷号：3
DOI：10.1038/srep03073
出版社：Springer Nature
摘要：Particularly in Sr₂IrO₄, the interplay between spin-orbit coupling, bandwidth and on-site Coulomb repulsion stabilizes a J _eff = 1/2 spin-orbital entangled insulating state at low temperatures. Whether this insulating phase is Mott- or Slater-type, has been under intense debate. We address this issue via spatially resolved imaging and spectroscopic studies of the Sr₂IrO₄ surface using scanning tunneling microscopy/spectroscopy (STM/S). STS results clearly illustrate the opening of an insulating gap (150 ~ 250 meV) below the Néel temperature (T_N), in qualitative agreement with our density-functional theory (DFT) calculations. More importantly, the temperature dependence of the gap is qualitatively consistent with our DFT + dynamical mean field theory (DMFT) results, both showing a continuous transition from a gapped insulating ground state to a non-gap phase as temperatures approach T_N. These results indicate a significant Slater character of gap formation, thus suggesting that Sr₂IrO₄ is a uniquely correlated system, where Slater and Mott-Hubbard-type behaviors coexist.