We studied the electronic band structure of pulsed laser deposition (PLD) grown (111)-oriented ${\mathrm{SrRuO}}_3$ thin films using in situ angle-resolved photoemission spectroscopy technique. We observed light bands with a renormalized quasiparticle effective mass of about $0.8m_e$. The electron-phonon coupling underlying this mass renormalization yields a characteristic “kink” in the band dispersion. The self-energy analysis using the Einstein model suggests five optical phonon modes covering an energy range of 44–90 meV contribute to the coupling. In addition, we show that the quasiparticle spectral intensity at the Fermi level is considerably suppressed, and two prominent peaks appear in the valance band spectrum at binding energies of 0.8 and 1.4 eV, respectively. We discuss the possible implications of these observations. Overall, our work demonstrates that high-quality thin films of oxides with large spin-orbit coupling can be grown along the polar (111) orientation by the PLD technique, enabling in situ electronic band structure study. This could allow for characterizing the thickness-dependent evolution of band structure of (111) heterostructures—a prerequisite for exploring possible topological quantum states in the bilayer limit.

中文翻译：

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（111）SrRuO3薄膜的电子能带结构：角分辨光电子能谱研究

我们研究了（111）取向的脉冲激光沉积（PLD）的电子能带结构 ${锶}_3$薄膜采用原位角分辨光发射光谱技术。我们观察到重新标准化的准粒子有效质量约为的光带$0.8{米}_{Ë}$。质量重归一化的基础上的电子-声子耦合会在谱带色散中产生特征性的“扭曲”。使用爱因斯坦模型进行的自能分析表明，涵盖了44–90 meV能量范围的五个光学声子模式有助于耦合。此外，我们显示费米能级的准粒子光谱强度被显着抑制，并且在价带谱中分别在0.8和1.4 eV的结合能处出现两个突出的峰。我们讨论了这些观察的可能含义。总的来说，我们的工作表明，利用PLD技术，可以沿极性（111）方向生长具有大自旋轨道耦合的高质量氧化物薄膜，从而可以实现原位生长电子乐队结构研究。这可以表征（111）异质结构能带厚度随厚度变化的特征，这是探索双层极限中可能的拓扑量子态的先决条件。