Europhys. Lett.
Volume 60, Number 2, October 2002
Page(s) 288 - 294
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 October 2002
DOI: 10.1209/epl/i2002-00349-x

Europhys. Lett., 60 (2) , pp. 288-294 (2002)

Partial and macroscopic phase coherences in an underdoped $\chem{Bi_{2}Sr_{2}CaCu_{2}O_{8+{\delta}}}$ thin film

H. 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 $_{8+{\delta}}$. It was observed that a superconducting gap and a pseudogap coexist in the superconducting state. The pseudogap locally evolves below $T^* \simeq 210$ 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 $T_{\rm S}\sim 95$ 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