# Pairing instability near a lattice-influenced nematic quantum critical point

## TL;DR

This paper investigates how lattice effects influence the enhancement of superconducting transition temperature near a nematic quantum critical point, revealing conditions under which Tc is significantly affected or remains unchanged.

## Contribution

It introduces a criterion to distinguish when Tc is enhanced or unaffected near a nematic QCP, considering lattice coupling effects and pairing interactions.

## Key findings

- Negligible Tc enhancement occurs if pairing is non-nematic and electron-strain coupling is strong.
- Lattice coupling restricts nematic criticality to certain directions, enabling weak-coupling analysis.
- Iron superconductors likely do not exhibit Tc enhancement near nematic QCP due to these effects.

## Abstract

We study how superconducting Tc is affected as an electronic system in a tetragonal environment is tuned to a nematic quantum critical point (QCP). Including coupling of the electronic nematic variable to the relevant lattice strain restricts criticality only to certain high symmetry directions. This allows a weak-coupling treatment, even at the QCP. We develop a criterion distinguishing weak and strong Tc enhancements upon approaching the QCP. We show that negligible Tc enhancement occurs only if pairing is dominated by a non-nematic interaction away from the QCP, and simultaneously if the electron-strain coupling is sufficiently strong. We argue this is the case of the iron superconductors.