"Critical divergence of the symmetric (A1g) nonlinear elastoresistance near the nematic transition in an iron-based superconductor"

J. C. Palmstrom: A. T. Hristov, S. A. Kivelson, J.-H. Chu, and I. R. Fisher; Physical Review B, 11/17/17.

Additional Authors: A. T. Hristov, S. A. Kivelson, J.-H. Chu, and I. R. Fisher

Abstract:

We report the observation of a nonlinear elastoresistivity response for the prototypical underdoped iron pnictide Ba(Fe0.975Co0.025)2As2. Our measurements reveal a large quadratic term in the isotropic (A1g) electronic response that was produced by a purely shear (B2g) strain. The divergence of this quantity upon cooling towards the structural phase transition reflects the temperature dependence of the nematic susceptibility. This observation shows that nematic fluctuations play a significant role in determining even the isotropic properties of this family of compounds.