Shi, M.Bendounan, A.Razzoli, E.Rosenkranz, S.Norman, M. R.Campuzano, J. C.Chang, Johan JuulMansson, M.Sassa, Y.Claesson, T.Tjernberg, O.Patthey, L.Momono, N.Oda, M.Ido, M.Guerrero, S.Mudry, C.Mesot, J.2010-11-302010-11-302010-11-30200910.1209/0295-5075/88/27008https://infoscience.epfl.ch/handle/20.500.14299/59612WOS:000271963700032Angle-resolved photoemission on underdoped La1.895Sr0.105CuO4 reveals that in the pseudogap phase, the dispersion has two branches located above and below the Fermi level with a minimum at the Fermi momentum. This is characteristic of the Bogoliubov dispersion in the superconducting state. We also observe that the superconducting and pseudogaps have the same d-wave form with the same amplitude. Our observations provide direct evidence for preformed Cooper pairs, implying that the pseudogap phase is a precursor to superconductivity. Copyright (C) EPLA, 2009High-T-CUnderdoped Bi2212Normal-StateSuperconductorsGapBi2Sr2Cacu2O8+Deltatext::journal::journal article::research article