Doping evolution of the quasiparticle excitations in heavily hole-doped Ba 1 - X K x Fe 2 As 2: A possible superconducting gap with sign-reversal between hole pockets

D. Watanabe, T. Yamashita, Y. Kawamoto, S. Kurata, Y. Mizukami, T. Ohta, S. Kasahara, M. Yamashita, T. Saito, H. Fukazawa, Y. Kohori, S. Ishida, K. Kihou, C. H. Lee, A. Iyo, H. Eisaki, A. B. Vorontsov, T. Shibauchi, Y. Matsuda

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

To gain insight into the unconventional superconductivity of Fe pnictides with no electron pockets, we measure the thermal conductivity κ and penetration depth λ in the heavily hole-doped regime of Ba1-xKxFe2As2. The residual thermal conductivity (κ/T)T→0K and T dependence of λ consistently indicate the fully gapped superconductivity at x=0.76 and the (line) nodal superconductivity at higher hole concentrations. The magnitude of κTTc|T→0K and the slope of λ(T) at low temperatures, both of which are determined by the properties of the low-energy excitations, exhibit a highly unusual nonmonotonic x dependence. These results indicate a dramatic change of the nodal characteristics in a narrow doping range. We suggest that the observed x dependence is naturally explained by a doping crossover of the gap function between the s-wave states with and without sign reversal between Γ-centered hole pockets.

Original languageEnglish
Article number115112
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume89
Issue number11
DOIs
Publication statusPublished - Mar 11 2014
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint

Dive into the research topics of 'Doping evolution of the quasiparticle excitations in heavily hole-doped Ba 1 - X K x Fe 2 As 2: A possible superconducting gap with sign-reversal between hole pockets'. Together they form a unique fingerprint.

Cite this