Superconductivity around nematic quantum critical point in two-dimensional metals

TL;DR

This paper investigates how nematic quantum criticality influences s-wave superconductivity in two-dimensional metals, revealing that the critical point maximizes the gap and that interplay with other pairing interactions can significantly enhance superconductivity.

Contribution

It provides a self-consistent analysis of superconductivity near a nematic quantum critical point, including the effects of Landau damping and additional pairing interactions, without linearization.

Findings

Superconducting gap peaks at the nematic quantum critical point.

The interplay with other pairing interactions can amplify the superconducting gap.

Superconductivity can be significantly enhanced through combined nematic and bosonic interactions.

Abstract

We study the properties of $s$-wave superconductivity induced around a nematic quantum critical point in two-dimensional metals. The strong Landau damping and the Cooper pairing between incoherent fermions have dramatic mutual influence on each other, and hence should be treated on an equal footing. This problem is addressed by analyzing the self-consistent Dyson-Schwinger equations for the superconducting gap and Landau damping rate. We solve the equations at zero temperature without making any linearization, and show that the superconducting gap is maximized at the quantum critical point and decreases rapidly as the system departs from this point. The interplay between nematic fluctuation and an additional pairing interaction, caused by phonon or other boson mode, is also investigated. The total superconducting gap generated by such interplay can be several times larger than the direct sum of the gaps separately induced by these two pairing interactions. This provides a promising way to achieve remarkable enhancement of superconductivity.