Quasiparticle scattering in a superconductor near a nematic critical point: resonance mode and multiple attractive channels

TL;DR

This paper studies how soft nematic fluctuations influence quasiparticle scattering in a 2D superconductor, revealing a complex spectral structure due to competing pairing channels and nematic resonance effects.

Contribution

It introduces a detailed analysis of quasiparticle scattering near a nematic critical point, highlighting the role of multiple pairing channels and nematic resonance in shaping the spectral features.

Findings

Scattering rate is significantly altered by all pairing channels beyond the gap.

Spectral features include a 'peak-peak-dip-hump' structure similar to cuprates.

Nematic resonance and competing channels determine the energy-dependent scattering behavior.

Abstract

We analyze the scattering rate for 2D fermions interacting via soft nematic fluctuations. The ground state is an s-wave superconductor, but other pairing channels are almost equally attractive. This strongly alters the scattering rate: At energies beyond the pairing gap $\Delta$, it is renormalized by contributions from all pairing channels. At energies of order $\Delta$, it is determined by the competition between scattering into a gapped continuum and dispersing nematic resonance. The outcome is a "peak-peak-dip-hump" spectrum, similar, but not identical, to the "peak-dip-hump" structure in the cuprates.