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SUMMARY:Femtosecond Photodoping Phenomena in Cuprate high-Tc Superconducto
 rs 
DTSTART:20120322T153000
DTEND:20120322T170000
DTSTAMP:20260506T080357Z
UID:ab8ab4ec85c4e784c11dcbfefadd295f022ba8248c50acaa77a92a62
CATEGORIES:Conferences - Seminars
DESCRIPTION:Jure Demsar\n\nPhysics Department\, University of Konstanz\, D
 -78457 Konstanz\, Germany\n\nUltrafast processes in superconductors (in pa
 rticular in high-Tc cuprates) excited with femtosecond optical pulses have
  been intensively studied for over two decades. While most of the studies 
 have been performed in a simple single-color optical pump-probe configurat
 ion\, novel broad band spectrally resolved studies are being used nowadays
  to obtain detailed information about the interplay between various degree
 s of freedom (electrons\, spin\, lattice) and their interaction strengths.
 \n\nIn this seminar I will first present the recent systematic study of su
 perconducting gap dynamics in a standard BCS superconductor NbN [1]. Based
  on this benchmark study I will review the findings obtained on high-Tc cu
 prates\, focusing in particular on results obtained with time-resolved THz
  techniques which enable direct access to the SC condensate [2\,3\,4] and 
 high frequency phonon dynamics [4].\n\nFollowing this I will present the f
 irst systematic photodoping studies of La2-xSrxCuO4 (0<x<0.35)\, aiming at
  determining the nature of low energy excitations in cuprates and its evol
 ution upon doping the charge-transfer insulating ground state. In particul
 ar\, by studying the dynamics of the complex dielectric function over 0.5-
 2.8 eV range as a function of excitation conditions important information 
 about the nature of mid-infrared absorption and charge-transfer excitation
 s can be obtained\, challenging the existing theoretical models.\n\n\n\n[1
 ] M. Beck\, et al.\, Phys. Rev. Lett. 107\, 177007 (2011).\n\n[2] R. D. Av
 eritt et al.\, Phys. Rev. B 63\, 140502(R) (2001)\; R. A. Kaindl et al.\, 
 Phys. Rev. B 72\, 060510 (2005)\; J. Demsar et al.\, Phys. Rev. Lett. 91\,
  267002 (2003)\; R. A. Kaindl et al.\, Science 287\, 470 (2000).\n\n[3] M.
  Beyer\, et al.\, Phys. Rev. B 83\, 214515 (2011).\n\n[4] A. Pashkin\, et 
 al.\, Phys. Rev. Lett. 105\, 067001 (2010).\n
LOCATION:CH G1 495 https://plan.epfl.ch/?room==CH%20G1%20495
STATUS:CONFIRMED
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