Europhys. Lett., 60 (2) , pp. 288-294 (2002)
Partial and macroscopic phase coherences in an underdoped thin filmH. Murakami1, T. Kiwa1, N. Kida1, M. Tonouchi1, T. Uchiyama2, I. Iguchi2 and Z. Wang3
1 Research Center for Superconductor Photonics, Osaka University and CREST-JST 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
2 Department of Physiscs, Tokyo Institute of Technology and CREST-JST 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
3 Kansai Advanced Research Center, Communication Research Laboratory Kobe 651-2492, Japan
(Received 21 May 2002; accepted 25 July 2002)
A combined study using the time-resolved pump-probe technique and the time domain terahertz transmission spectroscopy has been carried out to investigate the normal-state anomalies in underdoped Bi 2Sr 2CaCu 2O . It was observed that a superconducting gap and a pseudogap coexist in the superconducting state. The pseudogap locally evolves below K simultaneously with the appearance of partial phase coherence with a short lifetime less than 1 ps. With decreasing temperature, the domains with a pseudogap developed and saturated at K, and the frequency-dependent superconductivity fluctuation appeared as cooperative phenomena among the partial phase-coherent domains. These experimental data show that the development of the partial coherent local domains with a pseudogap has an important role to switch from the partial to the macroscopic phase-coherent state.
74.25.-q - General properties; correlations between physical properties in normal and superconducting states.
74.25.Nf - Response to electromagnetic fields (nuclear magnetic resonance, surface impedance, etc.).
74.72.Hs - Bi-based cuprates.
© EDP Sciences 2002