Emergence of superconducting gap features in Bi2Sr2CaCu2O8+delta single crystals from intrinsic c-axis interlayer tunneling

TL;DR

This paper investigates the emergence of superconducting gap features in Bi2Sr2CaCu2O8+delta single crystals through transport measurements, revealing insights into interlayer tunneling and pseudogap phenomena near optimal doping.

Contribution

It provides experimental evidence of coherent interlayer tunneling and gap features in both superconducting and normal states of Bi2Sr2CaCu2O8+delta crystals.

Findings

Zero bias conductance minimum indicates a pseudogap.

Superconducting gap features appear at Tc.

High coherence in interlayer tunneling observed.

Abstract

Static and dynamic transport measurements on stacks of intrinsic Josephson junctions on Bi2Sr2CaCu2O8+delta single crystals, near to optimal doping, are presented. The zero bias minimum in dynamic conductance is consistent with a normal state pseudo-gap. At Tc, a critical current develops simultaneously with new features consistent with a gap in the superconducting density states at an already well-established energy. The lack of thermal broadening and the small scale of the features force us to conclude a high degree of coherent interlayer tunneling in both the superconducting and normal states.