Effect of bilayer coupling on tunneling conductance of double-layer high T_c cuprates

TL;DR

This paper investigates how bilayer coupling affects tunneling conductance in high-Tc cuprates, explaining why bilayer splitting peaks are often not clearly observed in experiments due to broadening effects.

Contribution

It provides a theoretical analysis of bilayer coupling effects on tunneling spectra, accounting for peak suppression and broadening in high-Tc cuprates.

Findings

Bilayer coupling causes splitting of coherence peaks into bonding and antibonding bands.

Particle-hole asymmetry and finite quasiparticle lifetime suppress and broaden the bonding peak.

The results explain the experimental difficulty in observing bilayer splitting in tunneling measurements.

Abstract

Physical effects of bilayer coupling on the tunneling spectroscopy of high T$_{c}$ cuprates are investigated. The bilayer coupling separates the bonding and antibonding bands and leads to a splitting of the coherence peaks in the tunneling differential conductance. However, the coherence peak of the bonding band is strongly suppressed and broadened by the particle-hole asymmetry in the density of states and finite quasiparticle life-time, and is difficult to resolve by experiments. This gives a qualitative account why the bilayer splitting of the coherence peaks was not clearly observed in tunneling measurements of double-layer high-T$_c$ oxides.