Superconducting gap symmetry in the superconductor BaFe(1.9)Ni(0.1)As(2)статьяИсследовательская статья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 10 августа 2018 г.
Аннотация:We report on the Andreev spectroscopy and specific heat of high-quality single crystals of BaFe(1.9)Ni(0.1)As(2). The intrinsic multiple Andreev reflection spectroscopy reveals two anisotropic superconducting gaps Δ_L = 3.2 - 4.5 meV, Δ_S = 1.2 - 1.6 meV (the ranges correspond to the minimum and maximum value of the coupling energy in the k_x-k_y plane). The 25%-30% anisotropy shows the absence of nodes in the superconducting gaps. Using a two-band model with s-wave-like gaps Δ_L = 3.2 meV and Δ_S = 1.6 meV, the temperature dependence of the electronic specific heat can be well described. A linear magnetic field dependence of the low-temperature specific heat offers further support of s-wave type of the order parameter. We find that a d-wave or single-gap BCS theory under the weak-coupling approach cannot describe our experiments.