Superconducting and pseudogap states studied by using interlayer Tunneling Spectroscopy on Bi2Sr2CaCu2O8+x single crystals

Abstract

The existence of a superconducting gap and a pseudogap, and the correlation between them, in cuprates is believed to provide a key to understanding the mechanism of high-T-c superconductivity. In this study. constant-temperature interlayer tunneling spectroscopy measurements were made on stacks of Bi2Sr2CaCu2O8+(y) intrinsic junctions, excluding the bias-induced self-heating effect. In a certain range of temperatures near T, the bias-dependent tunneling spectral distribution showed a peak-dip-hump structure, indicating the coexistence of superconducting and pseudogap states. In a Tesla-range c-axis magnetic field, the spectral weight of the coherence peak diminished, filling mainly the dip region, indicating a major contribution of the dip-region spectral weight to the superconducting condensation.