Published February 24, 2011
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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
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.
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.Attached Files
Published - Teague2011p12935Phys_Rev_Lett.pdf
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Teague2011p12935Phys_Rev_Lett.pdf
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Additional details
- Eprint ID
- 22945
- Resolver ID
- CaltechAUTHORS:20110316-154916963
- DMR-0907251
- NSF
- Kavli Nanoscience Institute
- National Natural Science Foundation of China
- Ministry of Science and Technology (China)
- Chinese Academy of Sciences
- Gordon and Betty Moore Foundation
- Created
-
2011-03-16Created from EPrint's datestamp field
- Updated
-
2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Kavli Nanoscience Institute