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Measurement of a Sign-Changing Two-Gap Superconducting Phase in Electron-Doped Ba(Fe_(1-x)Co_x)_2As_2 Single Crystals Using Scanning Tunneling Spectroscopy

Teague, M. L. and Drayna, G. K. and Lockhart, G. P. and Cheng, P. and Shen, B. and Wen, H.-H. and Yeh, N.-C. (2011) Measurement of a Sign-Changing Two-Gap Superconducting Phase in Electron-Doped Ba(Fe_(1-x)Co_x)_2As_2 Single Crystals Using Scanning Tunneling Spectroscopy. Physical Review Letters, 106 (8). Art. No. 087004. ISSN 0031-9007. http://resolver.caltech.edu/CaltechAUTHORS:20110316-154916963

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Abstract

Scanning tunneling spectroscopic studies of Ba(Fe_(1-x)Co_x)_2As_2 (x = 0.06, 0.12) single crystals reveal direct evidence for predominantly two-gap superconductivity. These gaps decrease with increasing temperature and vanish above the superconducting transition T_c. The two-gap nature and the slightly doping- and energy-dependent quasiparticle scattering interferences near the wave vectors (± π, 0) and (0, ± π) are consistent with sign-changing s-wave superconductivity. The excess zero-bias conductance and the large gap-to-T_c ratios suggest dominant unitary impurity scattering.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1103/PhysRevLett.106.087004DOIArticle
http://prl.aps.org/abstract/PRL/v106/i8/e087004PublisherArticle
ORCID:
AuthorORCID
Yeh, N.-C.0000-0002-1826-419X
Additional Information:© 2011 American Physical Society. Received 13 July 2010; published 24 February 2011. The work at Caltech was jointly supported by NSF Grant No. DMR-0907251, and the Kavli and Moore Foundations. The work in China was supported by the NSFC, the Ministry of Science and Technology of China, and the Chinese Academy of Sciences within the knowledge innovation program. We thank Patrick A. Lee, Igor Mazin, and Yunkyu Bang for valuable discussions.
Group:Kavli Nanoscience Institute
Funders:
Funding AgencyGrant Number
NSFDMR-0907251
Kavli Nanoscience InstituteUNSPECIFIED
National Natural Science Foundation of ChinaUNSPECIFIED
Ministry of Science and Technology (China)UNSPECIFIED
Chinese Academy of SciencesUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
Classification Code:PACS: 74.20.Rp, 74.25.Jb, 74.55.+v, 74.70.Xa
Record Number:CaltechAUTHORS:20110316-154916963
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20110316-154916963
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22945
Collection:CaltechAUTHORS
Deposited By: Benjamin Perez
Deposited On:16 Mar 2011 23:07
Last Modified:16 Nov 2017 21:39

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