Superconductivity with broken time-reversal symmetry inside a superconducting s-wave state

Grinenko , Sarkar R, Kihou K, Lee CH, Morozov , Aswartham S, Buechner B, Chekhonin P, Skrotzki W, Nenkov K, Huehne R, Nielsch K, Drechsler SL, Vadimovs VL, Silaev MA, Volkov PA, Eremin , Luetkens H, Klauss HH (2020)

Publication Type: Journal article

Publication year: 2020

Journal

Nature Physics Nature Research

Book Volume: 16

Pages Range: 789-794

Journal Issue: 7

DOI: 10.1038/s41567-020-0886-9

Abstract

In general, magnetism and superconductivity are antagonistic to each other. However, there are several families of superconductors in which superconductivity coexists with magnetism, and a few examples are known where the superconductivity itself induces spontaneous magnetism. The best known of these compounds are Sr2RuO4 and some non-centrosymmetric superconductors. Here, we report the finding of a narrow dome of an s+ is^′ superconducting phase with apparent broken time-reversal symmetry (BTRS) inside the broad s-wave superconducting region of the centrosymmetric multiband superconductor Ba1 − xKxFe2As2 (0.7 ≲ x ≲ 0.85). We observe spontaneous magnetic fields inside this dome using the muon spin relaxation (μSR) technique. Furthermore, our detailed specific heat study reveals that the BTRS dome appears very close to a change in the topology of the Fermi surface. With this, we experimentally demonstrate the likely emergence of a novel quantum state due to topological changes of the electronic system.

Involved external institutions

National Institute of Advanced Industrial Science and Technology / 産業技術総合研究所 (AIST)

Japan (JP) Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden e.V. (IFW) / Leibniz Institute for Solid State and Materials Research Dresden

Germany (DE) Technische Universität Dresden

Germany (DE) Ruhr-Universität Bochum (RUB)

Germany (DE) Russian Academy of Sciences / Росси́йская акаде́мия нау́к (RAS)

Russian Federation (RU) University of Jyväskylä / Jyväskylän yliopisto

Finland (FI) Paul Scherrer Institute (PSI)

Switzerland (CH)

How to cite

APA:

Grinenko, ., Sarkar, R., Kihou, K., Lee, C.H., Morozov, ., Aswartham, S.,... Klauss, H.-H. (2020). Superconductivity with broken time-reversal symmetry inside a superconducting s-wave state. Nature Physics, 16(7), 789-794. https://doi.org/10.1038/s41567-020-0886-9

MLA:

Grinenko, , et al. "Superconductivity with broken time-reversal symmetry inside a superconducting s-wave state." Nature Physics 16.7 (2020): 789-794.

BibTeX: Download