Electron-plasmon interaction induced plasmonic-polaron band replication in epitaxial perovskite SrIrO3 films

• Published in: Science bulletin (Beijing) Vol. 66; no. 5; pp. 433 - 440
• Main Authors: Liu, Zhengtai, Liu, Wanling, Zhou, Ruixiang, Cai, Songhua, Song, Yekai, Yao, Qi, Lu, Xiangle, Liu, Jishan, Liu, Zhonghao, Wang, Zhen, Zheng, Yi, Wang, Peng, Liu, Zhi, Li, Gang, Shen, Dawei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-03-2021
• Subjects: 5d electron systems; Electron-plasmon interaction; perovskite SrIrO3; Replica bands; Electron-plasmon interaction; 5d electron systems; Replica bands; perovskite SrIrO3
• ISSN: 2095-9273
• DOI: 10.1016/j.scib.2020.10.003

Electron-boson interaction is fundamental to a thorough understanding of various exotic properties emerging in many-body physics. In photoemission spectroscopy, photoelectron emission due to photon absorption would trigger diverse collective excitations in solids, including the emergence of phonons, magnons, electron-hole pairs, and plasmons, which naturally provides a reliable pathway to study electron-boson couplings. While fingerprints of electron–phonon/-magnon interactions in this state-of-the-art technique have been well investigated, much less is known about electron-plasmon coupling, and direct observation of the band renormalization solely due to electron-plasmon interactions is extremely challenging. Here by utilizing integrated oxide molecular-beam epitaxy and angle-resolved photoemission spectroscopy, we discover the long sought-after pure electron-plasmon coupling-induced low-lying plasmonic-polaron replica bands in epitaxial semimetallic SrIrO3 films, in which the characteristic low carrier concentration and narrow bandwidth combine to provide a unique platform where the electron-plasmon interaction can be investigated kinematically in photoemission spectroscopy. This finding enriches the forms of electron band normalization on collective modes in solids and demonstrates that, to obtain a complete understanding of the quasiparticle dynamics in 5d electron systems, the electron-plasmon interaction should be considered on equal footing with the acknowledged electron–electron interaction and spin–orbit coupling.