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arXiv · 1605.01908

Superconducting gap structure of FeSe

Lin Jiao·Chien-Lung Huang·Sahana Rößler·Cevriye Koz·Ulrich K. Rößler·Ulrich Schwarz·Steffen Wirth
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Abstract

The microscopic mechanism governing the zero-resistance flow of current in some iron-based, high-temperature superconducting materials is not well understood up to now. A central issue concerning the investigation of these materials is their superconducting gap symmetry and structure. Here we present a combined study of low-temperature specific heat and scanning tunnelling microscopy measurements on single crystalline FeSe. The results reveal the existence of at least two superconducting gaps which can be represented by a phenomenological two-band model. The analysis of the specific heat suggests significant anisotropy in the gap magnitude with deep gap minima. The tunneling spectra display an overall "U"-shaped gap close to the Fermi level away as well as on top of twin boundaries. These results are compatible with the anisotropic nodeless models describing superconductivity in FeSe.

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Lin Jiao, Chien-Lung Huang, Sahana Rößler, Cevriye Koz, Ulrich K. Rößler, Ulrich Schwarz, Steffen Wirth. 2016-05-06. Superconducting gap structure of FeSe. https://doi.org/10.1038/srep44024

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