Study of pseudogap phenomena by STM and other probes

The temperature and doping dependence of The tunneling spectrum of Bi2.1Sr1 .9CaCu2O, single crystals was obtained by using a low-temperature scanning tunneling microscope. Above T-c, for x less than or equal to 8.27, the tunn eling density of states shows a clear gap-like feature with a larger gap va lue than the superconducting one, while for x > 8.27, it shows the feature expected from the conventional superconducting fluctuation SCF. We determin ed the SCF component in the static susceptibility (chi) BY subtracting the effect of the SCF from chi, we confirmed that the two pseudogap phase bound aries determined by the tunneling and chi coincide with each other. (C) 200 0 Elsevier Science Ltd. Ail rights reserved.