Effect of structural supermodulation on superconductivity in tri-layer cuprate Bi2Sr2Ca2Cu3O10+x

TL;DR

This study explores how structural supermodulation influences superconductivity in tri-layer cuprate Bi2Sr2Ca2Cu3O10+x, revealing doping-dependent variations and a novel two-gap spectrum linked to interlayer interactions.

Contribution

It uncovers the impact of structural supermodulation on superconducting properties and introduces a new two-gap tunneling spectrum in tri-layer cuprates.

Findings

Superconducting gap and coherence peak vary periodically with supermodulation.

Two-gap spectra emerge with increased doping, linked to supermodulation.

Interlayer interactions between CuO2 planes influence superconducting features.

Abstract

We investigate the spatial and doping evolutions of the superconducting properties of tri-layer cuprate Bi2Sr2Ca2Cu3O10+x by using scanning tunneling microscopy and spectroscopy. Both the superconducting coherence peak and gap size exhibit periodic variations with the structural supermodulation, but the effect is much more pronounced in the underdoped regime than at optimal doping. Moreover, a new type of tunneling spectrum characterized by two superconducting gaps emerges with increasing doping, and the two-gap features also correlate with the supermodulation. We propose that the interaction between the inequivalent outer and inner CuO2 planes is responsible for these novel features that are unique to tri-layer cuprates.