title: Divergent nematic susceptibility in an iron arsenide superconductor.
abstract: Within the Landau paradigm of continuous phase transitions, ordered states of matter are characterized by a broken symmetry. Although the broken symmetry is usually evident, determining the driving force behind the phase transition can be complicated by coupling between distinct order parameters. We show how measurement of the divergent nematic susceptibility of the iron pnictide superconductor Ba(Fe(1-x)Co(x))(2)As(2) distinguishes an electronic nematic phase transition from a simple ferroelastic distortion. These measurements also indicate an electronic nematic quantum phase transition near the composition with optimal superconducting transition temperature.
authors.affiliation: Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA. jhchu@berkeley.edu
authors.forename: Jiun-Haw
authors.initials: JH
authors.lastname: Chu
authors.forename: Hsueh-Hui
authors.initials: HH
authors.lastname: Kuo
authors.forename: James G
authors.initials: JG
authors.lastname: Analytis
authors.forename: Ian R
authors.initials: IR
authors.lastname: Fisher