Spectroscopic evidence of nematic fluctuations in LiFeAs

The role of nematic fluctuations in the pairing mechanism of iron-based superconductors is frequently debated. Here we present a novel method to reveal such fluctuations by identifying energy and momentum of the corresponding nematic boson through the detection of a boson-assisted resonant amplifica...

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Bibliographic Details
Published in:arXiv.org 2018-11
Main Authors: Sun, Zhixiang, Nag, Pranab Kumar, Sykora, Steffen, Guevara, Jose M, Hoffmann, Sven, Salazar, Christian, Hänke, Torben, Kappenberger, Rhea, Wurmehl, Sabine, Büchner, Bernd, Hess, Christian
Format: Article
Language:English
Subjects:
Anomalies
Fourier transforms
Momentum
Spectroscopy
Spectrum analysis
Unconventional superconductors
Variation
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Summary:The role of nematic fluctuations in the pairing mechanism of iron-based superconductors is frequently debated. Here we present a novel method to reveal such fluctuations by identifying energy and momentum of the corresponding nematic boson through the detection of a boson-assisted resonant amplification of Friedel oscillations. Using Fourier-transform scanning tunneling spectroscopy, we observe for the unconventional superconductor LiFeAs strong signatures of bosonic states at momentum \(q\sim 0\) and energy \(\Omega\approx8\)~meV. We show that these bosonic states survive in the normal conducting state, and, moreover, that they are in perfect agreement with well-known strong above-gap anomalies in the tunneling spectra. Attributing these small-\(q\) boson modes to nematic fluctuations we provide the first spectroscopic approach to the nematic boson in an unconventional superconductor.
ISSN:2331-8422
DOI:10.48550/arxiv.1811.03489