The coherence peak of unconventional superconductors in the charge channel

TL;DR

This paper investigates the coherence peak in the charge channel of unconventional superconductors, revealing its presence in various materials and proposing nuclear quadrupole relaxation as an effective detection method.

Contribution

It demonstrates the existence of a coherence peak in the charge channel of unconventional superconductors and highlights nuclear quadrupole relaxation as a novel detection technique.

Findings

Coherence peak observed below T_c in charge channel of d-wave cuprates

Nuclear quadrupole relaxation effectively detects the coherence peak

Similar coherence peaks found in ultrasonic attenuation and iron-based superconductors

Abstract

In this work, we carry out a systematic investigation of the coherence peak in unconventional superconductors as they transition into the superconducting phase at $T_c$. Using $d$-wave cuprates as an example, we reveal the presence of a coherence peak below $T_c$ in the charge channel. The nuclear quadrupole relaxation rate is shown to be an effective method for detecting this unconventional coherence peak, with the superconducting coherence factor playing a pivotal role in its emergence. Additionally, we explore the influence of correlation effects, which further enhance this phenomenon. Extending our analysis, we demonstrate the existence of a similar coherence peak in ultrasonic attenuation and iron-based superconductors. Our findings offer a fresh perspective on probing superconducting gap symmetry in unconventional superconductors.