Scrutinizing the double superconducting gaps and strong coupling pairing in (Li(1-x)Fe(x))OHFeSe.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 26822281.
- Also identified by DOI 10.1038/ncomms10565 and PMC identifier 4740187.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
In the field of iron-based superconductors, one of the frontier studies is about the pairing mechanism. The recently discovered (Li(1-x)Fe(x))OHFeSe superconductor with the transition temperature of about 40 K provides a good platform to check the origin of double superconducting gaps and high transition temperature in the monolayer FeSe thin film. Here we report a scanning tunnelling spectroscopy study on the (Li(1-x)Fe(x))OHFeSe single crystals. The tunnelling spectrum mimics that of the monolayer FeSe thin film and shows double gaps at about 14.3 and 8.6 meV. Further analysis based on the quasiparticle interference allows us to rule out the d-wave gap, and for the first time assign the larger (smaller) gap to the outer (inner) Fermi pockets (after folding) associating with the dxy (dxz/dyz) orbitals, respectively. The gap ratio amounts to 8.7, which demonstrates the strong coupling mechanism in the present superconducting system.