T. E. Kuzmicheva, S. A. Kuzmichev, A. V. Sadakov, A. V. Muratov, A. S. Usoltsev, V. P. Martovitsky, A. R. Shipilov, D. A. Chareev, E. S. Mitrofanova, V. M. Pudalov, “Direct evidence of two superconducting gaps in FeSe<nobr>$_{0.5}$</nobr>Te<nobr>$_{0.5}$</nobr>: SnS-Andreev spectroscopy and lower critical field”, Pis'ma v Zh. Èksper. Teoret. Fiz., 2016, Volume 104, Issue 12,Page 864

This article is cited in 5 papers

CONDENSED MATTER

Direct evidence of two superconducting gaps in FeSe$_{0.5}$Te$_{0.5}$: SnS-Andreev spectroscopy and lower critical field

T. E. Kuzmicheva^a, S. A. Kuzmichev^ab, A. V. Sadakov^a, A. V. Muratov^a, A. S. Usoltsev^a, V. P. Martovitsky^a, A. R. Shipilov^b, D. A. Chareev^cde, E. S. Mitrofanova^b, V. M. Pudalov^a

^a Lebedev Physical Institute, Russian Academy of Sciences, Moscow, Russia
^b Moscow State University, Moscow, Russia
^c Kazan Federal University, Kazan, Russia
^d Institute of Physics and Technology, Ural Federal University, Yekaterinburg, Russia
^e Institute of Experimental Mineralogy, Russian Academy of Sciences, Chernogolovka, Moscow region, Russia

Abstract: We present direct measurements of the superconducting order parameter in nearly optimal FeSe Te single crystals with the critical temperature $T_C\approx14$ K. Using the intrinsic multiple Andreev reflection effect (IMARE) spectroscopy and measurements of the lower critical field, we directly determined two superconducting gaps, $\Delta_{\mathrm{L}}\approx 3.3$–$3.4$ meV and $\Delta S\approx 1$ meV, and their temperature dependences. We show that a twoband model fits well the experimental data. The estimated electron–boson coupling constants indicate a strong intraband and a moderate interband interaction.

Received: 03.11.2016

Language: English

DOI: 10.7868/S0370274X16240073