Two distinct superconducting phases in LiFeAs

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Date
2016
Volume
6
Issue
Journal
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Book Title
Publisher
London : Nature Publishing Group
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Abstract

A non-trivial temperature evolution of superconductivity including a temperature-induced phase transition between two superconducting phases or even a time-reversal symmetry breaking order parameter is in principle expected in multiband superconductors such as iron-pnictides. Here we present scanning tunnelling spectroscopy data of LiFeAs which reveal two distinct superconducting phases: at = 18 K a partial superconducting gap opens, evidenced by subtle, yet clear features in the tunnelling spectra, i.e. particle-hole symmetric coherence peak and dip-hump structures. At Tc = 16 K, these features substantiate dramatically and become characteristic of full superconductivity. Remarkably, the distance between the dip-hump structures and the coherence peaks remains practically constant in the whole temperature regimeT ≤ . This rules out the connection of the dip-hump structures to an antiferromagnetic spin resonance.

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Keywords
Electronic properties and materials, Superconducting properties and materials
Citation
Nag, P. K., Schlegel, R., Baumann, D., Grafe, H.-J., Beck, R., Wurmehl, S., et al. (2016). Two distinct superconducting phases in LiFeAs. 6. https://doi.org//10.1038/srep27926
License
CC BY 4.0 Unported