Particle-hole asymmetric superconducting coherence peaks in overdoped cuprates

TL;DR

This study uses scanning tunneling microscopy to reveal particle-hole asymmetry and unusual interference patterns in overdoped cuprates, shedding light on the superconductor-metal transition at the end of the superconducting dome.

Contribution

It uncovers particle-hole asymmetry and non-dispersive interference patterns at coherence peaks, proposing a new explanation involving pairing-breaking scattering in overdoped cuprates.

Findings

Particle-hole asymmetry modulates with sqrt(2)*sqrt(2) periodicity.

Non-dispersive interference patterns emerge at coherence peaks.

Pairing-breaking scattering causes the observed phenomena.

Abstract

To elucidate the superconductor to metal transition at the end of superconducting dome, the overdoped regime has stepped onto the center stage of cuprate research recently. Here, we use scanning tunneling microscopy to investigate the atomic-scale electronic structure of overdoped trilayer Bi-2223 and bilayer Bi-2212 cuprates. At low energies the spectroscopic maps are well described by dispersive quasiparticle interference patterns. However, as the bias increases to the superconducting coherence peak energy, a virtually non-dispersive pattern with sqrt(2)*sqrt(2) periodicity emerges. Remarkably, the position of the coherence peaks exhibits evident particle-hole asymmetry which also modulates with the same period. We propose that this is an extreme quasiparticle interference phenomenon, caused by pairing-breaking scattering between flat anti-nodal Bogoliubov bands, which is ultimately responsible for the superconductor to metal transition.