ISSP - The institute for Solid State Physics

Seminar
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LASORセミナー:Non-equilibrium electronic structure of transient, laser-excited states in Bi-2212
標題: LASORセミナー:Non-equilibrium electronic structure of transient, laser-excited states in Bi-2212
日時: 2014年10月3日(金)  午後4:00~
場所: 物性研究所本館6階 大講義室(A632)  
講師: Prof. U. Bovensiepen
所属: University Duisburg-Essen
要旨: Optical excitations in solid materials typically decay on femto- to picosecond time scales due to elementary interactions which lead to a redistribution of the excess energy among the electronic, the lattice, and the spin subsystem, before final dissipation. In femtosecond time-resolved experiments ultrafast dynamical changes are analyzed in order to shed light on the nature and the dynamics of the superconducting state in high-Tc materials. Femtosecond optical and THz spectroscopy are powerful methods here [1-3]. Recently a transient dynamic coherence was reported far above Tc [4]. Femtosecond time and angle-resolved photoemission spectroscopy (tr-ARPES) [5] probes the electronic structure directly in the presence of optical excitations and opens new opportunities to investigate the influence of collective excitations on the single particle spectral function. Tr-ARPES has been employed to analyze the response of the electronic structure to optical excitations in optimally doped Bi-2212 below Tc [6,7]. In this talk, we discuss the transient electronic structure above Tc at 100 K. We analyze an increased electronic mass and quantify an effective hole photo-doping [8]. We further discuss changes of the relaxation times in the vicinity of the 70 meV kink energy above the Fermi energy originating from to coupling to a Boson mode and recent results obtained for underdoped Bi-2212.
世話人: 渡辺 浩 (内線:63377)
e-mail: hwata :at: issp.u-tokyo.ac.jp
詳細ページ: 要旨
http://www.issp.u-tokyo.ac.jp/issp_wms/DATA/OPTION/abstract20141003.doc