Nematic Glassy Behavior Probed by NMR under Strain in Iron Pnictide Superconductors

ORAL

Abstract

NMR studies of Ba(M_xFe_1-x)2As2 (M = Co, Cu) have uncovered
inhomogeneous glassy dynamics via stretched exponential relaxation and
wipeout of the NMR signal. These signatures emerge below approximately
100-150 K, depending on the doping level, and reach a maximum onset
temperature around the nematic quantum critical point. Here we
present NMR data under uniaxial strain in Ba(CoxFe1-x)2As2 (x=0.08) at
the nematic quantum critical point. The relaxation behavior reveals
inhomogeneous relaxation that is strongly temperature-dependent and
hysteretic with strain. The stretching exponent, which probes the
degree of inhomogeneity, remains unchanged under strain. These results
suggest that the inhomogeneous relaxation observed by NMR reflects a
nematic glass, in which large random strain fields are present and
frustrate long-range nematic order.

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Presenters

  • Tanat Kissikov

    University of California, Davis

Authors

  • Tanat Kissikov

    University of California, Davis

  • Makariy Tanatar

    Ames Laboratory, Ames Laboratory US DOE, Ames, Iowa, Ames Laboratory and Iowa State University, Ames, IA, USA, Ames Laboratory and Department of Physics & Astronomy, Iowa State University, Ames, IA 50010, USA

  • Paul Canfield

    Ames Laboratory and Dept. of Physics, Iowa State University, Ames Laboratory, U.S. DOE, Iowa State University, Ames, Iowa 50011, USA., Ames Laboratory, Iowa State University, Department of Physics, Iowa State University, Ames Laboratory, Ames, Iowa 50011, USA, Ames Laboratory, Iowa State University, Ames Laboratory/Iowa State University, Iowa State University and Ames Laboratory, Ames Laboratory and Iowa State University, Ames, IA, USA, Ames Laboratory and Dept. of Phys. and Astro.,, Iowa State Univ., Ames Laboratory and Department of Physics & Astronomy, Iowa State University, Ames, IA 50010, USA, Ames Lab & Dept of Physics and Astronomy, Iowa State University, Department of Physics & Astronomy, Iowa State University, Department of physics and astronomy, Iowa State University/Ames Laboratory, Physics, Iowa State University/Ames Laboratory, Ames Laboratory & Iowa State University, Physics, Iowa State University

  • Erica Carlson

    Purdue University, Department of Physics and Astronomy, Purdue University

  • Karin Andrea Dahmen

    University of Illinois at Urbana-Champaign

  • Nicholas Curro

    University of California, Davis