title: Two-gap superconductivity in Ba1-xKxFe2As2: a complementary study of the magnetic penetration depth by muon-spin rotation and angle-resolved photoemission.
abstract: We investigate the magnetic penetration depth lambda in superconducting Ba1-xKxFe2As2 (Tc approximately 32 K) with muon-spin rotation (microSR) and angle-resolved photoemission (ARPES). Using microSR, we find the penetration-depth anisotropy gamma lambda=lambda c/lambda ab and the second-critical-field anisotropy gammaHc2 to show an opposite T evolution below Tc. This dichotomy resembles the situation in the two-gap superconductor MgB2. A two-gap scenario is also suggested by an inflection point in the in-plane penetration depth lambda ab around 7 K. The complementarity of microSR and ARPES allows us to pinpoint the values of the two gaps and to arrive to a remarkable agreement between the two techniques concerning the full T evolution of lambdaab. This provides further support for the described scenario and establishes ARPES as a tool to assess macroscopic properties of the superconducting condensate.
authors.affiliation: Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland. rustem.khasanov@psi.ch
authors.forename: R
authors.initials: R
authors.lastname: Khasanov
authors.forename: D V
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authors.lastname: Evtushinsky
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authors.lastname: Amato
authors.forename: H-H
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authors.lastname: Klauss
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authors.lastname: Luetkens
authors.forename: Ch
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authors.lastname: Niedermayer
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authors.lastname: Büchner
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authors.lastname: Sun
authors.forename: C T
authors.initials: CT
authors.lastname: Lin
authors.forename: J T
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authors.lastname: Park
authors.forename: D S
authors.initials: DS
authors.lastname: Inosov
authors.forename: V
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authors.lastname: Hinkov