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