Analysis of nonlinear conductivity of point contacts on the base of FeSe in the normal and superconducting state

Автор(и)

  • Yu.G. Naidyuk B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
  • N.V. Gamayunova B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
  • O.E. Kvitnitskaya B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine 47 Lenin Ave., Kharkov 61103, Ukraine
  • G. Fuchs Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e.V., Postfach 270116 Dresden D-01171, Germany
  • D.A. Chareev Institute of Experimental Mineralogy, Russian Academy of Sciences, Chernogolovka 142432, Moscow District, Russia
  • A.N. Vasiliev Low Temperature Physics and Superconductivity Department, Physics Faculty, M.V. Lomonosov Moscow State University Moscow 119991, Russia

DOI:

https://doi.org/10.1063/1.4939153%20

Ключові слова:

iron-chalcogenide superconductors, point-contacts, Andreev reflection spectroscopy, energy gap.

Анотація

Nonlinear conductivity of point contacts (PCs) on the base of FeSe single crystals has been investigated. Measured dV/dI dependencies demonstrate the prevailing contribution to the PC conductivity caused by the degraded surface. Superconducting (SC) feature in dV/dI like a sharp zero-bias minimum develops for relatively low ohmic PCs, where the deep areas of FeSe are involved. Analysis of dV/dI has shown that the origin of the zero-bias minimum is connected with the Maxwell part of the PC resistance, what masks energy dependent spectral peculiarities. Even so, we have found the specific features in dV/dI — the sharp side maxima, which may have connection to the SC gap, since their position follows the BCS temperature dependence. Exploring the dV/dI spectra of the rare occurrence with Andreev-like structure, the two gaps with Δ = 2.5 and 3.5 meV were identified.

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Опубліковано

2015-11-17

Як цитувати

(1)
Naidyuk, Y.; Gamayunova, N.; Kvitnitskaya, O.; Fuchs, G.; Chareev, D.; Vasiliev, A. Analysis of Nonlinear Conductivity of Point Contacts on the Base of FeSe in the Normal and Superconducting State. Fiz. Nizk. Temp. 2015, 42, 42-48.

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