title: In-plane resistivity anisotropy in an underdoped iron arsenide superconductor.
abstract: High-temperature superconductivity often emerges in the proximity of a symmetry-breaking ground state. For superconducting iron arsenides, in addition to the antiferromagnetic ground state, a small structural distortion breaks the crystal's C(4 )rotational symmetry in the underdoped part of the phase diagram. We reveal that the representative iron arsenide Ba(Fe(1)(-x)Co(x))(2)As(2) develops a large electronic anisotropy at this transition via measurements of the in-plane resistivity of detwinned single crystals, with the resistivity along the shorter b axis rho(b) being greater than rho(a). The anisotropy reaches a maximum value of ~2 for compositions in the neighborhood of the beginning of the superconducting dome. For temperatures well above the structural transition, uniaxial stress induces a resistivity anisotropy, indicating a substantial nematic susceptibility.
authors: Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA 94305, USA.
authors: Jiun-Haw
authors: JH
authors: Chu
authors: James G
authors: JG
authors: Analytis
authors: Kristiaan
authors: K
authors: De Greve
authors: Peter L
authors: PL
authors: McMahon
authors: Zahirul
authors: Z
authors: Islam
authors: Yoshihisa
authors: Y
authors: Yamamoto
authors: Ian R
authors: IR
authors: Fisher