The interaction of electrons with crystal lattice vibrations (phonons) and collective charge-density fluctuations (plasmons) influences profoundly the spectral properties of solids revealed by photoemission spectroscopy experiments. Photoemission satellites, for instance, are a prototypical example of quantum emergent behavior that may result from the strong coupling of electronic states to plasmons and phonons. The existence of these spectral features has been verified over energy scales spanning several orders of magnitude (from 50 meV to 15-20 eV) and for a broad class of compounds such as simple metals, semiconductors, and highly-doped oxides. During the past few years the cumulant expansion approach, alongside with the GW approximation and the theory of electron-phonon and electron-plasmon coupling in solids, has evolved into a predictive and quantitatively accurate approach for the description of the spectral signatures of electron-boson coupling entirely from first principles, and it has thus become the state-of-the-art theoretical tool for the description of these phenomena. In this chapter we introduce the fundamental concepts needed to interpret plasmon and phonon satellites in photoelectron spectra, and we review recent progress on first-principles calculations of these features using the cumulant expansion method.
Nonperturbative quantum theory of multiplasmonic electron emission from surfaces: Gauge-specific cumulant expansions vs. Volkov ansatz over plasmonic coherent states
Lifetime effects and satellites in the photoelectron spectrum of platinum metal
University College London（伦敦大学学院）；University of Oxford（牛津大学）；Istituto Officina dei Materiali (IOM)-CNR, Laboratorio TASC（意大利材料研究所（IOM）-国家研究委员会，TASC实验室）；Barcelona Supercomputing Center（巴塞罗那超级计算中心）；University of Bristol（布里斯托大学）；UiT The Arctic University of Norway（挪威北极大学）；Université Paris-Saclay（巴黎萨克雷大学）；HarwellXPS, Research Complex at Harwell, Rutherford Appleton Laboratory（哈维尔XPS，哈韦尔研究中心，卢瑟福阿普尔顿实验室）
Lifetime effects and satellites in the photoelectron spectrum of tungsten metal
钨是一种重要且用途广泛的过渡金属，在许多技术的核心中占有一席之地。X射线光电子能谱学（XPS）是表征钨和钨基化合物的一种流行的实验技术，它能够通过收集芯能级和价带谱来评估化学状态和电子结构。然而，在金属钨的情况下，关于在光电子谱中突出的卫星特征的起源、性质和位置仍然存在悬而未决的问题。这些卫星是材料电子结构的指纹，尚未得到彻底的研究，有时会导致误解。本工作结合了高分辨软、硬X射线光电子能谱学（SXPS和HAXPES）与反射电子能量损失谱（REELS）和多层从头算理论方法，包括密度泛函理论（DFT）和多体微扰理论（G 0 W 0和GW+C），解开复杂的实验观察到的卫星功能归因于等离子体激元和带间跃迁的产生。这种实验-理论相结合的策略能够揭示以前未记录的卫星特征，提高我们对它们与钨电子结构直接关系的理解。此外，它奠定了基础，为未来的研究钨基混合金属系统，并持有承诺，重新评估的光电子光谱的其他过渡和后过渡金属，类似的问题，关于卫星功能仍然存在。
