Effects of nematic fluctuations on the elastic properties of iron arsenide superconductors

TL;DR

This study shows that nematic fluctuations significantly influence the elastic properties of iron arsenide superconductors, with lattice softening and hardening linked to nematic and magnetic fluctuations.

Contribution

The paper introduces a model connecting nematic fluctuations to elastic property changes in FeAs superconductors, supported by resonant ultrasound spectroscopy data.

Findings

Lattice softening in the normal phase explained by nematic fluctuations

Lattice hardening in the superconducting phase linked to magnetic fluctuations

Structural order driven by magnetic fluctuations

Abstract

We demonstrate that the changes in the elastic properties of the FeAs systems, as seen in our resonant ultrasound spectroscopy data, can be naturally understood in terms of fluctuations of emerging nematic degrees of freedom. Both the softening of the lattice in the normal, tetragonal phase as well as its hardening in the superconducting phase are consistently described by our model. Our results confirm the view that structural order is induced by magnetic fluctuations.