Pressure dependent resistivity and magnetic measurements on superconducting KFe$_2$As$_2$

ORAL

Abstract

Ba$_{1-x}$K$_x$Fe$_2$As$_2$ shows superconductivity at $T_c\approx 38$~K at the optimal doping ($x\approx 0.4$). However, superconductivity is still observed up to the extreme hole doping ($x=1$) in KFe$_2$As$_2$ with a reduced $T_c\approx 3.4$~K. At this extreme limit, there is no observed electron pocket in this compound. The superconducting state is believed to be of a different symmetry than in the other 122 iron based superconductors. By means of resistivity, magnetization and AC susceptibility under pressure, we investigate the properties of this material. The pressure dependence of $T_c$ has a change of slope around $2$~GPa possibly consistent with a transition to a superconducting state of a different symmetry [F. F. Tafti, et al., Nature Physics 9, 349 (2013)]. We will compare measurements performed in different pressure media and discuss the evolution of the electronic correlations with applied pressure. Work at Ames Laboratory supported by AFOSR-MURI grant FA9550-09-1-0603 and by US DOE under the Contract No. DE-AC02-07CH11358. Work at Washington University supported by NSF Grant No. DMR-1104742 and by the Carnegie/DOE Alliance Center through NNSA/DOE Grant No. DE-FC52-08NA28554.

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Authors

  • Udhara Kaluarachchi

    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Ames Lab, Department of Physics, Iowa State University

  • Valentin Taufour

    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Critical Material Institute, Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Ames Lab, Department of Physics, Iowa State University
    • The Ames Laboratory, Iowa State University, Ames, USA

  • M.A. Tanatar

    • Ames National Laboratory
    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Sherbrooke University
    • The Ames Laboratory, Ames, IA 50011, USA

  • Stella K. Kim

    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.

  • Yong Liu

    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.

  • Thomas A. Lograsso

    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.

  • S.L. Bud'ko

    • Ames Laboratory
    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Iowa State University, Ames Lab
    • Ames Laboratory/ Iowa State University
    • The Ames Laboratory, Ames, IA 50011, USA
    • The Ames Laboratory, Iowa State University, Ames, USA
    • Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University

  • Paul C. Canfield

    • Ames Laboratory, US DOE, Iowa State University, Ames, Iowa 50011, U.S.A.
    • Iowa State University, Ames Lab
    • Ames Laboratory/ Iowa State University
    • Iowa State University
    • Ames Laboratory
    • Iowa State Univ
    • Ames Laboratory and Dept. of Physics, Iowa State University
    • The Ames Laboratory, Ames, IA 50011, USA
    • Ames Lab, Department of Physics, Iowa State University
    • The Ames Laboratory, Iowa State University, Ames, USA
    • Ames Laboratory and Dept. of Physics and Astronomy, Iowa State University

  • Neda Foroozani

    • Physics Dept., Washington University, St. Louis, Missouri 63130, U.S.A.

  • Jinhyuk Lim

    • Physics Dept., Washington University, St. Louis, Missouri 63130, U.S.A.

  • James S. Schilling

    • Physics Dept., Washington University, St. Louis, Missouri 63130, U.S.A.