An infrared study of the pancake vortex state in La$_{2-x}$Sr$_{x}$CuO$_{4}$ across the phase diagram

ORAL

Abstract

We report on a doping dependent study of the far-infrared interlayer response in the high-temperature superconductor La$_{2-x}$Sr$_{x}$CuO$_{4}$ (La214). A magnetic field up to 8 Tesla applied perpendicular to the CuO$_{2}$ planes is found to increasingly suppress the Josephson plasma resonance (JPR) with decreased doping. By 6 Tesla at a temperature of 8 Kelvin, the c-axis reflectivity is identical to that of the normal state in the most underdoped samples, suggesting the sample is in a two dimensional superconducting state. This behavior is in contrast to fields parallel to the CuO$_{2}$ planes, where only a small suppression of the JPR is seen up to 17 Tesla. Vortex wandering and static spin density waves are considered as possible mechanisms for plane decoupling.

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Authors

  • Alexander Schafgans

    • Univ. of California, San Diego
    • Department of Physics, University of California, San Diego

  • Andrew LaForge

    • Univ. of California, San Diego
    • Department of Physics, University of California, San Diego

  • Sasa Dordevic

    • Department of Physics, The University of Akron

  • Muhammad Qazilbash

    • Department of Physics, University of California, San Diego

  • Seiki Komiya

    • Central Research Institute of Electric Power Industry, Iwato-kita, Komae, Tokyo

  • Yoichi Ando

    • Institute of Scientific and Industrial Research, Osaka University

  • Dimitri Basov

    • Univ. of California, San Diego
    • University of California San Diego
    • Department of Physics, University of California, San Diego
    • University of California, San Diego
    • University of California at San Diego