1998/01/07 by D. Mihailović, D. Mihailovic, Mihailovic, D. +10
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Magnetic and transport properties of perovskites and related materials #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con) #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/9801049
5 pages, 4 figures
arxiv created 1998/01/07 · openalex publication_date 1998/01/07 · arxiv updated 2009/11/30 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28
We report new time-resolved data of quasiparticle relaxation and Cooper pair recombination dynamics in YBa2Cu3O7-δ, measured as a function of temperature and doping δusing femtosecond optical spectroscopy. The data show the existence of a normal state pseudo-gap for in-plane charge excitations below T* and an unusual divergence of the quasiparticle relaxation time in the superconducting state τs with δtowards optimum doping. In the underdoped state, no change in the amplitude of the induced transmission (which is proportional to the DOS at EF), or relaxation time τs is observed at Tc. From the sum rule, both observations signify that no gap opens at Tc in underdoped YBCO for δ>0.15. Tc in this case only signifies the onset of phase coherence. The presented data thus suggest pair formation with an associated redistribution of the DOS starting at T* and the establishment of phase coherence at Tc consistent with Bose-Einstein condensation. In the optimally doped material, δ~ 0.1, on the other hand, both a divergence in lifetime and a change of the DOS occur at Tc, signifying the opening of a gap and the occurence of pairing takes place simultaneously.