Abstract

Alkaline-earth iron arsenide (122) is one of the most studied families of iron-based superconductors, especially for angle-resolved photoemission spectroscopy. While extensive photoemission results have been obtained, the surface complexity of 122 caused by its charge-non-neutral surface is rarely considered. Here, we show that the surface of 122 can be neutralized by potassium deposition. In potassium-coated BaFe2(As0.7P0.3)2, the surface-induced spectral broadening is strongly suppressed, and hence the coherent spectra that reflect the intrinsic bulk electronic state recover. This enables the measuring of superconducting gap with unpreceded precision. The result shows the existence of two pairing channels. While the gap anisotropy on the outer hole/electron pockets can be well fitted using an s± gap function, the gap anisotropy on the inner hole/electron shows a clear deviation. Our results provide quantitative constraints for refining theoretical models and also demonstrate an experimental method for revealing the intrinsic electronic properties of 122 in future studies.

The lack of a clean charge neutral cleavage plane for the 122 family of iron-based superconductors has complicated surface-sensitive spectroscopy probes from revealing the intrinsic electronic properties of these materials. Here the authors introduce an effective surface dosing method that drastically improves the observed spectral quality, thus revealing unprecedented details of the superconducting gap anisotropy.

Details

Title
Revealing the intrinsic superconducting gap anisotropy in surface-neutralized BaFe2(As0.7P0.3)2
Author
Xin Ziming 1 ; Wang, Yudi 1 ; Cai Cong 1 ; Wang, Zhengguo 1   VIAFID ORCID Logo  ; Chen, Lei 1 ; Han, Tingting 1   VIAFID ORCID Logo  ; Zhang, Yan 2   VIAFID ORCID Logo 

 Peking University, International Centre for Quantum Materials, School of Physics, Beijing, China (GRID:grid.11135.37) (ISNI:0000 0001 2256 9319) 
 Peking University, International Centre for Quantum Materials, School of Physics, Beijing, China (GRID:grid.11135.37) (ISNI:0000 0001 2256 9319); Collaborative Innovation Centre of Quantum Matter, Beijing, China (GRID:grid.11135.37) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
23993650
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2491437468
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.