Evidence for d-Wave Superconductivity in Single Layer FeSe/SrTiO3Probed by Quasiparticle Scattering Off Step Edges
In: Nano Letters, Jg. 19 (2019-03-07), Heft 4, S. 2497-2502
serialPeriodical
Zugriff:
The de Gennes extrapolation length is a direction dependent measure of the spatial evolution of the pairing gap near the boundary of a superconductor and thus provides a viable means to probe its symmetry. It is expected to be infinite and isotropic for plain s-wave pairing, and finite and anisotropic for d-wave. Here, we synthesize single-layer FeSe films on SrTiO3(001) (STO) substrates by molecular beam epitaxy and measure the de Gennes extrapolation length by scanning tunneling microscopy/spectroscopy. We find a 40% reduction of the superconducting gap near specular [110]Feedges, yielding an extrapolation length of 8.0 nm. However, near specular [010]Feedges, the extrapolation length is nearly infinite. These findings are consistent with a phase changing pairing with 2-fold symmetry, indicating d-wave superconductivity. This is further supported by the presence of in-gap states near the specular [110]Feedges, but not the [010]Feedges. This work provides direct experimental evidence for d-wave superconductivity in single-layer FeSe/STO and demonstrates quasiparticle scattering at boundaries to be a viable phase sensitive probe of pairing symmetry in Fe-based superconductors.
Titel: |
Evidence for d-Wave Superconductivity in Single Layer FeSe/SrTiO3Probed by Quasiparticle Scattering Off Step Edges
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Autor/in / Beteiligte Person: | Ge, Zhuozhi ; Yan, Chenhui ; Zhang, Huimin ; Agterberg, Daniel ; Weinert, Michael ; Li, Lian |
Zeitschrift: | Nano Letters, Jg. 19 (2019-03-07), Heft 4, S. 2497-2502 |
Veröffentlichung: | 2019 |
Medientyp: | serialPeriodical |
ISSN: | 1530-6984 (print) ; 1530-6992 (print) |
DOI: | 10.1021/acs.nanolett.9b00135 |
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