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Tracing the $s_\pm$-symmetry in iron pnictides by controlled disorder
- Source :
- Phys. Rev. B 93, 174515 (2016)
- Publication Year :
- 2015
-
Abstract
- Consecutive proton irradiation of iron pnictides reduces the superconducting transition temperature to decrease monotonically. Our systematic optical THz investigations of Ba(Fe$_{0.9}$Co$_{0.1}$)$_2$As$_2$ thin films reveal, however, that the low-energy superconducting gap is first suppressed, but recovers for higher irradiation doses. At the same time the decrease of the superfluid density with disorder comes to a halt. These observations are in excellent agreement with theoretical calculations, which predict a disorder-induced transition of the order parameter from $s_{\pm}$ to $s_{++}$ symmetry. Thereby we solve the longstanding puzzle of the iron pnictides gap symmetry in favor of $s_{\pm}$-symmetry and demonstrate THz spectroscopy as a tool to determine the symmetry of the superconducting order parameter.
- Subjects :
- Condensed Matter - Superconductivity
Subjects
Details
- Database :
- arXiv
- Journal :
- Phys. Rev. B 93, 174515 (2016)
- Publication Type :
- Report
- Accession number :
- edsarx.1511.05017
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1103/PhysRevB.93.174515