Anomaly in the tunneling I(V) characteristics of Bi2Sr2CaCu2O8+x

Tunneling measurements have been carried out on slightly overdoped Bi2Sr2CaCu2O8+x single crystals below and above the critical temperature by break-junctions and in-plane point-contacts. An anomaly was found in the tunneling I(V) characteristics. Analysis of the data shows that the anomaly is caused by the superconducting condensate. In the extracted I(V) characteristics of the condensate, the constant asymptotics points to the presence of one-dimensionality in Bi2212. The anomaly found here puts additional constraints on the final theory of high-Tc superconductivity.