Microwave Surface-Impedance Measurements of the Magnetic Penetration Depth in Single Crystal Ba1xKxFe2As2 Superconductors: Evidence for a Disorder-Dependent Superfluid Density

K. Hashimoto, T. Shibauchi, S. Kasahara, K. Ikada, S. Tonegawa, T. Kato, R. Okazaki, C. J. van der Beek, M. Konczykowski, H. Takeya, K. Hirata, T. Terashima, and Y. Matsuda
Phys. Rev. Lett. 102, 207001 – Published 19 May 2009

Abstract

We report high-sensitivity microwave measurements of the in-plane penetration depth λab and quasiparticle scattering rate 1/τ in several single crystals of the hole-doped Fe-based superconductor Ba1xKxFe2As2 (x0.55). While a power-law temperature dependence of λab with a power 2 is found in crystals with large 1/τ, we observe an exponential temperature dependence of the superfluid density consistent with the existence of fully opened two gaps in the cleanest crystal we studied. The difference may be a consequence of different levels of disorder inherent in the crystals. We also find a linear relation between the low-temperature scattering rate and the density of quasiparticles, which shows a clear contrast to the case of d-wave cuprate superconductors with nodes in the gap. These results demonstrate intrinsically nodeless order parameters in the Fe arsenides.

  • Figure
  • Figure
  • Figure
  • Figure
  • Received 20 October 2008

DOI:https://doi.org/10.1103/PhysRevLett.102.207001

©2009 American Physical Society

Authors & Affiliations

K. Hashimoto1, T. Shibauchi1, S. Kasahara2,3, K. Ikada1, S. Tonegawa1, T. Kato1, R. Okazaki1, C. J. van der Beek4, M. Konczykowski4, H. Takeya3, K. Hirata3, T. Terashima2, and Y. Matsuda1,4

  • 1Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
  • 2Research Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8502, Japan
  • 3National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan
  • 4Laboratoire des Solides Irradiés, Ecole Polytechnique, 91128 Palaiseau cedex, France

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 102, Iss. 20 — 22 May 2009

Reuse & Permissions
Access Options

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×