Unconventional charge density wave order in the pnictide superconductors Ba(Ni<sub>1-x</sub>Co<sub>x</sub>)<sub>2</sub>As<sub>2</sub> and Ba<sub>1-x</sub>Sr<sub>x</sub>Ni<sub>2</sub>As<sub>2</sub>

ORAL

Abstract

BaNi2As2 is a structural homologue of the pnictide high temperature superconductor parent compound, BaFe2As2, in which the Fe atoms are replaced by Ni. Superconductivity is highly suppressed in this system, reaching a maximum Tc = 2.3 K upon Co doping, compared to 24 K in its iron-based cousin, and the origin of this Tc suppression is not known. Using x-ray scattering, we present the discovery of CDW order in BaNi2As2 and its evolution upon Co and Sr doping. The chemical doping suppresses the CDW, paralleling the behavior of antiferromagnetism in iron-based superconductors. Our study demonstrates that pnictide superconductors can exhibit CDW order which may be closely related to the Tc suppression in this system. We also present the response of CDW in Ba1-xSrxNi2As2 under external strain and discuss how it relates to the strong nematic susceptibility recently discovered in these compounds via elastoresistivity measurements.

*X-ray work was supported by DOE grant DE-FG02-06ER46285 and crystal growth was supported by AFOSR grant FA9550-14-1-0332. P. A. and J. P. acknowledge Gordon and Betty Moore Foundation EPiQS grants GBMF4542 and GBMF4419, respectively.

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Presenters

  • Sangjun Lee

    • University of Illinois,Urbana Champaign
    • Department of Physics, Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign
    • University of Illinois Urbana Champaign
    • University of Illinois at Urbana-Champaign

Authors

  • Sangjun Lee

    • University of Illinois,Urbana Champaign
    • Department of Physics, Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign
    • University of Illinois Urbana Champaign
    • University of Illinois at Urbana-Champaign

  • Xiaolan Sun

    • University of Illinois at Urbana-Champaign

  • Xuefei Guo

    • University of Illinois at Urbana-Champaign

  • John Collini

    • University of Maryland, College Park
    • Department of Physics, University of Maryland, College Park

  • Chris Eckberg

    • University of Maryland, College Park
    • Physics Department, University of Maryland

  • Johnpierre Paglione

    • University of Maryland, College Park
    • Physics Department, University of Maryland
    • Maryland Quantum Materials Center, Department of Physics, University of Maryland College Park
    • Department of Physics, University of Maryland, College Park
    • University of Maryland, College Park & NIST
    • Univ of Maryland-Colege Park
    • Center for Quantum Materials, University of Maryland
    • Maryland Quantum Materials Center, Department of Physics, University of Maryland-College Park,College Park, Maryland 20742

  • Peter Abbamonte

    • University of Illinois at Urbana-Champaign
    • University of Illinois,Urbana Champaign