Gap spectroscopy in underdoped YBa$_2$Cu$_3$O$_{6+x}$ from superfluid spectral weight and intrinsic pair tunneling

ORAL

Abstract

Numerous experiments on cuprate high temperature superconductors reveal evidence for two different energy gaps: a normal state pseudogap that grows on underdoping, and a superconducting gap connected to the transition temperature $T_c$ [1]. Here we use two different experiments to probe the superconducting energy gap scale in highly underdoped YBa$_2$Cu$_3$O$_{6+x}$: intrinsic pair tunneling perpendicular to the CuO$_2$ planes; and measurements of in-plane superfluid spectral weight. The measurements have been carried out on special samples in which doping can be tuned continuously using controlled oxygen annealing at room temperature [2]. We present data for $T_c$ in the range of 3~K to 17~K, and show that the superconducting energy gap is indeed linked to $T_c$ (2$\Delta \sim 4 k_B T_c$), vanishing as $T_c \rightarrow 0$. \\[4pt] [1] H\"{u}fner \emph{et al.} Rep. Prog. Phys. 71, 062501 (2008)\\[0pt] [2] Broun \emph{et al.} Phys. Rev. Lett. 99, 237003 (2007)

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Authors

  • Wendell Huttema

    Simon Fraser University

  • Anthony Colaprete

    Triumf, Texas A\&M University, Tel Aviv University, TRIUMF, Simon Fraser University, Dept. of Physics, SFU, BC, Canada, Department of Physics and Astronomy, University of British Columbia, Cavendish Laboratory, University of Cambridge, Department of Physics, Simon Fraser University, University of British Columbia, University of Wisconsin-Madison, Brookhaven National Laboratory, Los Alamos National Laboratory, Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea, Department of Physics, Oregon State University, Corvallis, OR 97331-6507, Imago Scientific Instruments Corp., Department of Physics, Simon Fraser University, 8888 University Dr., Burnaby, BC, V5A 1S6 Canada, Linfield College, PNNL, University of Washington, University of Victoria, IUPUI1, Wabash, IUPUI2, Environmental Biotechnology Institute, University of Idaho, Moscow ID 83843, Physics Department, University of Idaho, Moscow ID 83843, Environmental Biotechnology Institute, University of Idaho, Moscow, ID 83844, Physics Department, University of Idaho, Moscow, Idaho 83844, TRIUMF / UBC, 5CSNSM-IN2P3-CNRS, Universit\'e Paris 11, University of Manitoba, Texas A\&M, U. Manitoba, Tel Aviv U., U. British Columbia, Universidad de Pa\'is Vasco, Department of Physics, University of Idaho, Moscow, Idaho 83844-0903, University of Idaho, Boise State University, Idaho State University, NASA Ames Research Center

  • Anthony Colaprete

    Triumf, Texas A\&M University, Tel Aviv University, TRIUMF, Simon Fraser University, Dept. of Physics, SFU, BC, Canada, Department of Physics and Astronomy, University of British Columbia, Cavendish Laboratory, University of Cambridge, Department of Physics, Simon Fraser University, University of British Columbia, University of Wisconsin-Madison, Brookhaven National Laboratory, Los Alamos National Laboratory, Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea, Department of Physics, Oregon State University, Corvallis, OR 97331-6507, Imago Scientific Instruments Corp., Department of Physics, Simon Fraser University, 8888 University Dr., Burnaby, BC, V5A 1S6 Canada, Linfield College, PNNL, University of Washington, University of Victoria, IUPUI1, Wabash, IUPUI2, Environmental Biotechnology Institute, University of Idaho, Moscow ID 83843, Physics Department, University of Idaho, Moscow ID 83843, Environmental Biotechnology Institute, University of Idaho, Moscow, ID 83844, Physics Department, University of Idaho, Moscow, Idaho 83844, TRIUMF / UBC, 5CSNSM-IN2P3-CNRS, Universit\'e Paris 11, University of Manitoba, Texas A\&M, U. Manitoba, Tel Aviv U., U. British Columbia, Universidad de Pa\'is Vasco, Department of Physics, University of Idaho, Moscow, Idaho 83844-0903, University of Idaho, Boise State University, Idaho State University, NASA Ames Research Center

  • Anthony Colaprete

    Triumf, Texas A\&M University, Tel Aviv University, TRIUMF, Simon Fraser University, Dept. of Physics, SFU, BC, Canada, Department of Physics and Astronomy, University of British Columbia, Cavendish Laboratory, University of Cambridge, Department of Physics, Simon Fraser University, University of British Columbia, University of Wisconsin-Madison, Brookhaven National Laboratory, Los Alamos National Laboratory, Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea, Department of Physics, Oregon State University, Corvallis, OR 97331-6507, Imago Scientific Instruments Corp., Department of Physics, Simon Fraser University, 8888 University Dr., Burnaby, BC, V5A 1S6 Canada, Linfield College, PNNL, University of Washington, University of Victoria, IUPUI1, Wabash, IUPUI2, Environmental Biotechnology Institute, University of Idaho, Moscow ID 83843, Physics Department, University of Idaho, Moscow ID 83843, Environmental Biotechnology Institute, University of Idaho, Moscow, ID 83844, Physics Department, University of Idaho, Moscow, Idaho 83844, TRIUMF / UBC, 5CSNSM-IN2P3-CNRS, Universit\'e Paris 11, University of Manitoba, Texas A\&M, U. Manitoba, Tel Aviv U., U. British Columbia, Universidad de Pa\'is Vasco, Department of Physics, University of Idaho, Moscow, Idaho 83844-0903, University of Idaho, Boise State University, Idaho State University, NASA Ames Research Center

  • Anthony Colaprete

    Triumf, Texas A\&M University, Tel Aviv University, TRIUMF, Simon Fraser University, Dept. of Physics, SFU, BC, Canada, Department of Physics and Astronomy, University of British Columbia, Cavendish Laboratory, University of Cambridge, Department of Physics, Simon Fraser University, University of British Columbia, University of Wisconsin-Madison, Brookhaven National Laboratory, Los Alamos National Laboratory, Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea, Department of Physics, Oregon State University, Corvallis, OR 97331-6507, Imago Scientific Instruments Corp., Department of Physics, Simon Fraser University, 8888 University Dr., Burnaby, BC, V5A 1S6 Canada, Linfield College, PNNL, University of Washington, University of Victoria, IUPUI1, Wabash, IUPUI2, Environmental Biotechnology Institute, University of Idaho, Moscow ID 83843, Physics Department, University of Idaho, Moscow ID 83843, Environmental Biotechnology Institute, University of Idaho, Moscow, ID 83844, Physics Department, University of Idaho, Moscow, Idaho 83844, TRIUMF / UBC, 5CSNSM-IN2P3-CNRS, Universit\'e Paris 11, University of Manitoba, Texas A\&M, U. Manitoba, Tel Aviv U., U. British Columbia, Universidad de Pa\'is Vasco, Department of Physics, University of Idaho, Moscow, Idaho 83844-0903, University of Idaho, Boise State University, Idaho State University, NASA Ames Research Center

  • Anthony Colaprete

    Triumf, Texas A\&M University, Tel Aviv University, TRIUMF, Simon Fraser University, Dept. of Physics, SFU, BC, Canada, Department of Physics and Astronomy, University of British Columbia, Cavendish Laboratory, University of Cambridge, Department of Physics, Simon Fraser University, University of British Columbia, University of Wisconsin-Madison, Brookhaven National Laboratory, Los Alamos National Laboratory, Department of Molecular Science and Technology, Ajou University, Suwon 443-749, Korea, Department of Physics, Oregon State University, Corvallis, OR 97331-6507, Imago Scientific Instruments Corp., Department of Physics, Simon Fraser University, 8888 University Dr., Burnaby, BC, V5A 1S6 Canada, Linfield College, PNNL, University of Washington, University of Victoria, IUPUI1, Wabash, IUPUI2, Environmental Biotechnology Institute, University of Idaho, Moscow ID 83843, Physics Department, University of Idaho, Moscow ID 83843, Environmental Biotechnology Institute, University of Idaho, Moscow, ID 83844, Physics Department, University of Idaho, Moscow, Idaho 83844, TRIUMF / UBC, 5CSNSM-IN2P3-CNRS, Universit\'e Paris 11, University of Manitoba, Texas A\&M, U. Manitoba, Tel Aviv U., U. British Columbia, Universidad de Pa\'is Vasco, Department of Physics, University of Idaho, Moscow, Idaho 83844-0903, University of Idaho, Boise State University, Idaho State University, NASA Ames Research Center