Tunneling Conductance Dependence of the Tunneling Spectra in Bi2Sr2CaCu2O8

Author: Sakata H.   Katagiri A.   Yokoi M.   Kato T.   Morimoto H.  

Publisher: Springer Publishing Company

ISSN: 0022-2291

Source: Journal of Low Temperature Physics, Vol.131, Iss.3-4, 2003-05, pp. : 275-279

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Abstract

We have measured the tunneling spectra in Bi2Sr2CaCu2O8 with a scanning tunneling microscope(STM) at various tip-sample distances by changing the tunneling conductance in a controlled manner. When the tunneling conductance is increased from 1×10-9 to 1×10-5 S, the spectra do not show changes in particular. However, the gap value decreases steeply and the asymmetric back ground density of states turns inverted V-shaped one above 6×10-4 S. The changes in the tunneling spectra at the high tunneling conductances are explained by the enhancement of the local carrier density induced by the pressure that the STM tip applied to the sample.