${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ has often been described via a simple, one-band pseudospin-$\frac{1}{2}$ model subject to electron-electron interactions on a square lattice, fostering analogies with cuprate superconductors believed to be well described by a similar model. In this work we argue—based on a detailed study of the low-energy electronic structure by circularly polarized spin and angle-resolved photoemission spectroscopy combined with dynamical mean-field theory calculations—that a pseudospin-$\frac{1}{2}$ model fails to capture the full complexity of the system. We show instead that a realistic multiband Hubbard Hamiltonian, accounting for the full correlated $t_{2g}$ manifold, provides a detailed description of the interplay between spin-orbital entanglement and electron-electron interactions and yields quantitative agreement with experiments. Our analysis establishes that the $j_{3/2}$ states make up a substantial percentage of the low-energy spectral weight, i.e., approximately 74% as determined from the integration of the $j$-resolved spectral function in the 0 to $-1.64\mathrm{eV}$ energy range. The results in our work are of relevance not only to Ir-based materials but also more generally to multiorbital materials with closely spaced energy scales.

中文翻译：

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Sr2IrO4二维赝自旋-12Mott绝缘体描述的约束

${锶}_2{\mathrm{氧化铁}}_4$经常通过简单的单波段伪自旋来描述$\frac{1}{2}$模型在方形晶格上受到电子 - 电子相互作用的影响，促进了与铜酸盐超导体的类比，这些超导体被认为可以被类似模型很好地描述。在这项工作中，我们认为——基于通过圆极化自旋和角分辨光电子能谱结合动态平均场理论计算对低能电子结构的详细研究——赝自旋-$\frac{1}{2}$模型未能捕捉到系统的全部复杂性。相反，我们展示了一个现实的多频带哈伯德哈密顿量，它解释了完全相关的${吨}_{2G}$歧管，提供了自旋轨道纠缠和电子 - 电子相互作用之间相互作用的详细描述，并与实验产生定量一致。我们的分析表明，$j_{3/2}$状态构成了低能谱权重的很大一部分，即大约 74%，由积分确定$j$-在 0 到解析谱函数$-1.64\mathrm{电子伏特}$能量范围。我们工作的结果不仅与基于 Ir 的材料相关，而且更普遍地与具有紧密间隔能量尺度的多轨道材料相关。