On the structure of the superconducting order parameter in high-temperature Fe-based superconductors

T.E. Kuzmicheva^a, b, A.V. Muratov^b, S.A. Kuzmichev^a, b, c, A.V. Sadakov^b, Yu.A. Aleshenko^b, V.A. Vlasenko^b, V.P. Martovitsky^b, K.S. Pervakov^b, d, Yu.F. Eltsev^b, V.M. Pudalov^b, e
^aLomonosov Moscow State University, Faculty of Physics, Leninskie Gory 1 build. 2, Moscow, 119991, Russian Federation
^bLebedev Physical Institute, Russian Academy of Sciences, Leninsky prosp. 53, Moscow, 119991, Russian Federation
^cLomonosov Moscow State University, Vorobevy Gory, Moscow, 119991, Russian Federation
^dInternational Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka str. 95, Wroclaw, 53-421, Poland
^eHSE University, ul. Myasnitskaya 20, Moscow, 101000, Russian Federation

This paper discusses the synthesis, characterization, and comprehensive study of Ba-122 single crystals with various substitutions and various T_c's. The paper uses five complementary techniques to obtain a self-consistent set of data on the superconducting properties of Ba-122. A major conclusion of the authors work is the coexistence of two superconducting condensates differing in the electron-boson coupling strength. The two gaps that develop in distinct Fermi surface sheets are nodeless in the k_xk_y-plane and exhibit s-wave symmetry, the two-band model represents a sufficient data description tool. A moderate interband coupling and a considerable Coulomb repulsion in the description of the two-gap superconducting state of barium pnictides favor the s⁺⁺-model.

Keywords: multi-gap superconductors, iron pnictides, specific heat, London penetration depth, Andreev spectroscopy, optics
PACS: 74.25.−q, 74.25.nd, 74.25.Ha, 74.45.+c, 74.70.Xa (all)
DOI: 10.3367/UFNe.2016.10.038002
URL: https://ufn.ru/en/articles/2017/4/g/
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000405325500007
Scopus

2-s2.0-85025159254
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2017PhyU...60..419K
Citation: Kuzmicheva T E, Muratov A V, Kuzmichev S A, Sadakov A V, Aleshenko Yu A, Vlasenko V A, Martovitsky V P, Pervakov K S, Eltsev Yu F, Pudalov V M "On the structure of the superconducting order parameter in high-temperature Fe-based superconductors" Phys. Usp. 60 419–429 (2017)

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@article{Kuzmicheva:2017,
	author = {T. E. Kuzmicheva and A. V. Muratov and S. A. Kuzmichev and A. V. Sadakov and Yu. A. Aleshenko and V. A. Vlasenko and V. P. Martovitsky and K. S. Pervakov and Yu. F. Eltsev and V. M. Pudalov},
	title = {On the structure of the superconducting order parameter in high-temperature Fe-based superconductors},
	publisher = {Physics-Uspekhi},
	year = {2017},
	journal = {Phys. Usp.},
	volume = {60},
	number = {4},
	pages = {419-429},
	url = {https://ufn.ru/en/articles/2017/4/g/},
	doi = {10.3367/UFNe.2016.10.038002}
}

Received: 7th, December 2016, accepted: 5th, October 2016

Оригинал: Кузьмичёва Т Е, Муратов А В, Кузьмичёв С А, Садаков А В, Алещенко Ю А, Власенко В А, Мартовицкий В П, Перваков К С, Ельцев Ю Ф, Пудалов В М «О структуре параметра порядка в высокотемпературных сверхпроводниках на основе железа» УФН 187 450–462 (2017); DOI: 10.3367/UFNr.2016.10.038002