The transport-structural correspondence across the nematic phase transition probed by elasto-x-ray diffraction

TL;DR

This study uses combined transport and x-ray diffraction measurements under tunable strain to explore the coupling between nematic order, lattice structure, and electronic transport in iron pnictide superconductors, revealing a nearly temperature-independent ratio of structural and transport quantities.

Contribution

It introduces elasto-XRD as a powerful method to simultaneously probe nematic fluctuations, structural changes, and transport properties within a single sample, advancing understanding of nemato-elastic and nemato-transport couplings.

Findings

The ratio of transport to structural quantities is nearly temperature-independent over 74 K.

Elasto-XRD effectively probes nematic fluctuations and couplings.

Large strain measurements reveal breakdown of mean field description and intertwined nematicity.

Abstract

Electronic nematicity in iron pnictide materials is coupled to both the lattice and the conducting electrons, which allows both structural and transport observables to probe nematic fluctuations and the order parameter. Here we combine simultaneous transport and x-ray diffraction measurements with in-situ tunable strain (elasto-XRD) to measure the temperature dependence of the shear modulus and elastoresistivity above the nematic transition and the spontaneous orthorhombicity and resistivity anisotropy below the nematic transition, all within a single sample of $Ba(Fe_{0.96}Co_{0.04})_{2} As_{2}$. The ratio of transport to structural quantities is nearly temperature-independent over a 74 K range and agrees between the ordered and disordered phases. These results show that elasto-XRD is a powerful technique to probe the nemato-elastic and nemato-transport couplings, which have important implications to the nearby superconductivity. It also enables the measurement in the large strain limit, where the breakdown of mean field description reveals the intertwined nature of nematicity.