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

• Published in: Физика низких температур
• Date: 2016
• Main Authors: Naidyuk, Yu.G., Gamayunova, N.V., Kvitnitskaya, O.E., Fuchs, G., Chareev, D.A., Vasiliev, A.N.
• Format: Article
• Language: English
• Published: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2016
• Subjects: Свеpхпpоводимость, в том числе высокотемпеpатуpная
• Online Access: https://nasplib.isofts.kiev.ua/handle/123456789/128447
• Journal Title: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Cite this: Analysis of nonlinear conductivity of point contacts on the base of FeSe in the normal and superconducting state / u.G. Naidyuk, N.V. Gamayunova, O.E. Kvitnitskaya, G. Fuchs, D.A. Chareev, A.N. Vasiliev // Физика низких температур. — 2016. — Т. 42, № 1. — С. 42–48. — Бібліогр.: 26 назв. — англ.

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.