Theoretical understanding of the quasiparticle dispersion in bilayer high-$T_{c}$ superconductors

TL;DR

This paper provides a theoretical analysis of quasiparticle dispersion in bilayer high-$T_c$ superconductors, comparing spin fluctuation and phonon interactions, and concludes spin resonance coupling dominates near antinodes based on experimental data.

Contribution

It offers a detailed theoretical comparison of spin fluctuation and phonon effects on quasiparticle dispersion, highlighting the dominant role of spin resonance in bilayer high-$T_c$ superconductors.

Findings

Both interactions cause a kink in dispersion near $(\pi,0)$.

Differences in lineshape and quasiparticle weight distinguish the interactions.

Spin resonance coupling is identified as the primary interaction in experiments.

Abstract

The renormalization of quasiparticle (QP) dispersion in bilayer high-$T_{c}$ cuprates is investigated theoretically by examining respectively the interactions of the QP with spin fluctuations (SF) and phonons. It is illustrated that both interactions are able to give rise to a kink in the dispersion around the antinodes (near $(\pi,0)$). However, remarkable differences between the two cases are found for the peak/dip/hump structure in the lineshape, the QP weight, and the interlayer coupling effect on the kink, which are suggested to serve as a discriminance to single out the dominant interaction in the superconducting state. A comparison to recent photoemission experiments shows clearly that the coupling to the spin resonance is dominant for the QP around antinodes in bilayer systems.