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Evidence for time-reversal symmetry breaking of the superconducting state near twin-boundary interfaces in FeSe revealed by scanning tunneling spectroscopy

Watashige, T.; Tsutsumi, Y.; Hanaguri, T.; Kohsaka, Y.; Kasahara, S.; Furusaki, A.; Sigrist, M.; Meingast, C. 1; Wolf, T. 1; Löhneysen, H. von 1; Shibauchi, T.; Matsuda, Y.
1 Institut für Festkörperphysik (IFP), Karlsruher Institut für Technologie (KIT)


unctions and interfaces consisting of unconventional superconductors provide an excellent experimental playground to study exotic phenomena related to the phase of the order parameter. Not only does the complex structure of unconventional order parameters have an impact on the Josephson effects, but it also may profoundly alter the quasiparticle excitation spectrum near a junction. Here, by using spectroscopic-imaging scanning tunneling microscopy, we visualize the spatial evolution of the LDOS near twin boundaries (TBs) of the nodal superconductor FeSe. The π/2 rotation of the crystallographic orientation across the TB twists the structure of the unconventional order parameter, which may, in principle, bring about a zero-energy LDOS peak at the TB. The LDOS at the TB observed in our study, in contrast, does not exhibit any signature of a zero-energy peak, and an apparent gap amplitude remains finite all the way across the TB. The low-energy quasiparticle excitations associated with the gap nodes are affected by the TB over a distance more than an order of magnitude larger than the coherence length ξ$_{ab}$. The modification of the low-energy states is even more prominent in the region between two neighboring TBs separated by a distance ≈7ξab. ... mehr

Volltext §
DOI: 10.5445/IR/110102100
DOI: 10.1103/PhysRevX.5.031022
Zitationen: 85
Zitationen: 90
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Festkörperphysik (IFP)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2015
Sprache Englisch
Identifikator ISSN: 2160-3308
KITopen-ID: 110102100
HGF-Programm 43.21.01 (POF III, LK 01) Quantum Correlations in Condensed Matter
Erschienen in Physical review / X
Verlag American Physical Society (APS)
Band 5
Seiten Art.Nr.: 031022
Nachgewiesen in Scopus
Web of Science
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