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SUMMARY:Seminar Miyai Yudai\, Hiroshima University\, "Evaluation of self-e
 nergy in heavily overdoped Bi2201  by angle-resolved photoemission spectro
 scopy"
DTSTART:20241009T090000Z
DTEND:20241009T100000Z
DTSTAMP:20260720T125400Z
UID:indico-event-8904@indico.fysik.su.se
CONTACT:sassa@kth.se
DESCRIPTION:Since the discovery of high transition-temperature superconduc
 tivity in cuprates\, extensive studies have been done to elucidate unusual
  physical properties such as metal-insulator transition\, pseudogap\, and 
 magnetic fluctuations [1–3]. To understand these unusual physical proper
 ties\, it is crucial to clarify the roles of the entangled many-body inter
 actions such as the electron-phonon interaction\, electron-electron intera
 ction\, and electron-magnon (spin wave) interaction. The characteristics o
 f these interactions are reflected in the functional form of the self-ener
 gy\, Σ(k\,ω\;T) which is embedded in the high-resolution angle-resolved 
 photoemission (ARPES) spectral shape. The major manifestation of the self-
 energy is the “kink structure” in the band dispersion\, and energy-dep
 endent linewidth broadening. In cuprate superconductors\, two characterist
 ic ARPES spectral features have been observed: the low-energy kink (LEK) a
 round -80 meV and the high-energy anomaly (HEA) around -300 meV. By extrac
 ting the self-energy from the ARPES spectrum\, one can clarify the many-bo
 dy interactions that induce unusual physical properties of cuprate superco
 nductors. However\, the self-energy responsible for the LEK and HEA have n
 ot been consistently evaluated\, and their origin and interrelationships h
 ave been elusive.\nIn this talk\, we present temperature-dependent many-bo
 dy interactions in heavily overdoped cuprate superconductor\, Bi2201\, usi
 ng high-resolution ARPES. By developing a new analysis method based on the
  Kramers-Kronig transformation\, we have successfully extracted self-energ
 ies corresponding to two distinct energy scales: the LEK and HEA. By compa
 ring our experimental data with theoretical calculations\, we found that t
 he magnitude of the self-energy for the LEK significantly enhanced upon co
 oling while that for HEA was almost temperature-independent. The temperatu
 re dependence of self-energy for the LEK cannot be explained solely by the
  electron-phonon interaction\, suggesting an unexplored enhancement mechan
 ism emerging from entangled many-body interactions. On the other hand\, th
 e self-energy responsible for the HEA is assumed to originate from the str
 ongly damped local excitations characterized by t (energy for charge trans
 fer) or J (energy for magnetic interaction with neighboring sites).\n[1] M
 . Imada et al.\, Rev. Mod. Phys. 70\, 1039 (1986)\n[2] M. Hashimoto et al
 .\, Nat. Phys. 10\, 483-495 (2014)\n[3] A. Kopp et al.\, Proc. Natl. Acad.
  Sci. 104\, 6123 (2007)\n\nhttps://indico.fysik.su.se/event/8904/
LOCATION:Albano 3: 5230 - Xenon (12 seats) (Albano Building 3)
URL:https://indico.fysik.su.se/event/8904/
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