LaIrIn⁵ is a reference compound of the heavy-fermion superconductor CeIrIn⁵. The lack of f electrons in LaIrIn⁵ indicates that there should not be any f electron participating in the construction of its Fermi surface. Thus the electronic structure comparison between LaIrIn5 and CeIrIn5 provides a good platform to study the properties of f electrons. Here angle-resolved photoemission spectroscopy (ARPES) measurements and density functional theory (DFT) calculations are performed to study the electronic structures of LaIrIn⁵ and CeIrIn⁵. We find the valence band structures of the two materials are similar to each other, except for the absence of f bands in LaIrIn⁵. By analyzing the Fermi crossings of the three conduction bands of the two materials quantitatively, we find the volumes of the electron pockets α and β around the M′ point become larger from LaIrIn⁵ to CeIrIn⁵, while the hole pocket γ around the Γ′ point becomes smaller. Together with the calculation results, we confirm that this is mainly originated from the f-electron contribution, while the lattice-constant difference between LaIrIn⁵ and CeIrIn⁵ only has a finite influence. We also give a summary of the f-electron character in its related Ce-115 heavy fermion compounds. Our results may be essential for the complete microscopic understanding of the 115 compounds and the related heavy-fermion systems.

中文翻译：

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LaIrIn 5的电子结构及其相关Ce-115化合物的f电子特性

LaIrIn ⁵是重金属超导体CeIrIn ⁵的参考化合物。LaIrIn ^5中缺乏f电子，这表明不应该有任何f电子参与其费米表面的构造。因此，LaIrIn5和CeIrIn5之间的电子结构比较为研究f电子的性质提供了一个很好的平台。在这里进行角分辨光发射光谱（ARPES）测量和密度泛函理论（DFT）计算，以研究LaIrIn ⁵和CeIrIn ⁵的电子结构。我们发现两种材料的价带结构彼此相似，只是在LaIrIn ^5中没有f带。。通过定量分析两种材料的三个导带的费米交点，我们发现，M'点附近的电子口袋α和β的体积从LaIrIn ⁵到CeErInIn ⁵变大，而Γ'周围的空穴口袋γ点变小。连同计算结果，我们确认这主要来自f电子贡献，而LaIrIn ⁵和CeIrIn ⁵之间的晶格常数差异仅具有有限的影响。我们还总结了其相关的Ce-115重费米化合物中的f电子特征。我们的结果对于完整微观了解115种化合物和相关的重费米子系统可能至关重要。