Divergent Nematic Susceptibility in an Iron Arsenide Superconductor

Abstract

Lattice Trailing the Electrons Superconducting order recedes with decreased chemical doping in a typical iron-based superconductor family. Thus, the symmetry of the material is broken by almost simultaneous antiferromagnetic and structural phase transitions. However, some pnictides also exhibit an electronic nematic transition manifested by anisotropy of the electrical resistance. Because this anisotropy occurs at the same time as the structural transition, it is not clear whether it is a consequence of the broken crystal lattice symmetry or its cause. Chu et al. (p. 710 ) performed constant strain experiments on the series Ba(Fe 1−x Co x ) 2 As 2 , which can distinguish between the two scenarios, and confirm that the electrons drive the lattice transition.