Nuclear Magnetic Resonance in Low-Symmetry Superconductors

TL;DR

This paper investigates the nuclear magnetic resonance relaxation rate in low-symmetry superconductors with accidental nodes, revealing a Hebel-Slichter-like peak persists despite disorder and interactions.

Contribution

It demonstrates that a Hebel-Slichter-like peak can occur without an isotropic gap component, challenging previous assumptions about its origins.

Findings

A Hebel-Slichter-like peak exists in superconductors with accidental nodes.

Disorder and electron-electron interactions do not eliminate the peak.

Logarithmic divergence is controlled by these effects but remains observable.

Abstract

We consider the nuclear spin-lattice relaxation rate, $1/T_1T$ in superconductors with accidental nodes. We show that a Hebel-Slichter-like peak occurs even in the absence of an isotropic component of the superconducting gap. The logarithmic divergence found in clean, non-interacting models is controlled by both disorder and electron-electron interactions. However, for reasonable parameters, neither of these effects removes the peak altogether.