\textit{d}-Wave Superconductivity and Quasiparticle Dynamics in $\rm KFe_2As_2$

ORAL

Abstract

Recent work in superconductivity focuses largely on unconventional superconductors that have a layered structure, such as the pnictide, $\rm KFe_2As_2$. Among other potential benefits, these tend to display a much higher critical temperature than conventional superconductors. It is always interesting to investigate the mechanism for forming Cooper pairs. In our experiment, we probe the nodal structure of the superconducting energy gap in $\rm KFe_2As_2$ to determine pairing symmetry by using milliKelvin microwave spectroscopy. We find that the superfluid density has a linear temperature dependence, which provides compelling evidence for line nodes and \textit{d}-wave pairing. We also investigate the relaxation dynamics of thermally excited quasiparticles, wherein we discover a rapid collapse in scattering below $\rm T_c$, much like the high-$\rm T_c$ cuprate superconductors. I will present surface impedance data taken at temperatures down to 0.1K, from which we obtain complex microwave conductivity and superfluid density.

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Authors

  • Megan A. Boothby

    Simon Fraser University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University

  • William H. Dowd

    Oregon State University, University of Washington, University of Hong Kong, University of Tennessee, Oak Ridge National Laboratory, University of British Columbia, Univ of Washington, Univ of Cambridge, Michigan State University, Universit\'e de Caen, Argonne National Laboratory, Texas A\&M University -Commerce, Texas A\&M University, Department of Physics, University of Idaho, Moscow, Idaho 83844, USA, Universidad de Salamanca, E-37008 Salamanca, Spain, Department of Physics, Florida State University, Tallahassee, Florida 32306, USA, University of Cambridge, Institute of Astronomy, University of Cambridge, Canadian Institute for Theoretical Astrophysics, University of Toronto, Seoul National University, Chungnam National University, Department of Physics, Oregon State University, TRIUMF, Roosevelt High School, Department of Physics, University of Washington, Oregon State Department of Chemistry, Oregon State School of Electrical Engineering and Computer Science, Oregon State Department of Physics, University of Idaho, Lawrence Livermore National Laboratory, Idaho National Laboratory, Pacific Northwest National Laboratory, Carnegie Institution of Washington, Department of Chemistry, Oregon State University, School of Electrical Engineering and Computer Science, Oregon State University, Washington State University, Harvard University, Idaho Accelerator Center, Idaho Accelerator Center, Idaho State University, 1500 Alvin Ricken drive, Pocatello, ID 83201, USA, CENPA, University of Washington, Physics Division, ANL, NSCL, Michigan State University, Division, ANL, LPC, CAEN, France, Paul Scherrer Institute, US Geological Survey, 12201 Sunrise Valley Drive, Reston, VA, 20192, USA, University of Calgary Department of Physics and Astronomy, University of Calgary Department of Geoscience, None, University of the Fraser Valley, Univ of California, Berkeley, Simon Fraser University, Los Alamos Natl. Lab., University of Science and Technology of China, Hefei, U of Washington, Georgia Institute of Technology, Washington State Univ, National Institute of Standards and Technology and University of Maryland, American University