Probing the Energy Gaps of a Multi-Gap Superconductor: Ba( 1-x)K x F e2 A s 2

Probing the Energy Gaps of a Multi-Gap Superconductor: Ba(1-x)KxFe2As2

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Keeran Ramanathan, Luke Conover, Oberon Wackwitz, and Roberto Ramos

University of the Sciences,Philadelphia, PA, 19104, USA
a) Corresponding author: r.ramos [at]


In order to spectroscopically probe the s uperconducting energy gap of potassium-doped Ba122 i ron pnictides, in particular Ba(1-x)KxFe2As2 where x = 0.33 (under-doped regime), we have performed four-wire conductance measurements from T = 2K to 52K. We report evidence for multi-gap features with gaps corresponding to directional tunneling through the ab - axes of this iron pnictide. The multi-gap features a predominant result o f tunneling across the ab - plane with gaps of Δ1 = 2-4 meV and Δ2 = 9-11 meV. These gap values are temperature dependent.