Nematic susceptibility of hole- and electron-doped BaFe2As2 iron-based superconductors from shear modulus measurements

TL;DR

This study measures the nematic susceptibility in hole- and electron-doped BaFe2As2 superconductors, revealing persistent nematic fluctuations across the superconducting dome and quantum critical behavior only in the electron-doped system.

Contribution

It provides the first systematic shear modulus measurements of nematic susceptibility in both hole- and electron-doped BaFe2As2, highlighting the role of nematic fluctuations in superconductivity.

Findings

Nematic fluctuations persist across the entire superconducting dome.

Quantum critical behavior observed only in electron-doped BaFe2As2.

Nematic susceptibility is weakened but extends with doping.

Abstract

The nematic susceptibility of hole-doped Ba1-xKxFe2As2 and electron-doped Ba(Fe1-xCox)2As2 iron-based superconductors is obtained from measurements of the elastic shear modulus using a three-point bending setup in a capacitance dilatometer. Nematic fluctuations, although weakened by doping, extend over the whole superconducting dome in both systems, suggesting their close tie to superconductivity. Evidence for quantum critical behavior of the nematic susceptibility is, surprisingly, only found for Ba(Fe1-xCox)2As2, the system with the lower maximal Tc value.