Evidence of nematic order and nodal superconducting gap along [110] direction in RbFe2As2
| Autor: | Qi Yao, Tong Zhang, Donglai Feng, Yajun Yan, Wei Chen, Thomas Wolf, Xi Liu, Mingqiang Ren, Ran Tao |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
0301 basic medicine
Science Rotational symmetry FOS: Physical sciences General Physics and Astronomy 02 engineering and technology Electronic structure Article General Biochemistry Genetics and Molecular Biology law.invention Superconductivity (cond-mat.supr-con) Condensed Matter - Strongly Correlated Electrons 03 medical and health sciences Liquid crystal law Condensed Matter::Superconductivity Symmetry breaking lcsh:Science Superconductivity Physics Multidisciplinary Strongly Correlated Electrons (cond-mat.str-el) Condensed matter physics Condensed Matter - Superconductivity General Chemistry 021001 nanoscience & nanotechnology Brillouin zone 030104 developmental biology Pairing lcsh:Q Scanning tunneling microscope 0210 nano-technology |
| Zdroj: | Nature Communications, Vol 10, Iss 1, Pp 1-12 (2019) Nature Communications |
| ISSN: | 2041-1723 |
| Popis: | Unconventional superconductivity often intertwines with various forms of order, such as the "nematic" order which breaks the rotational symmetry of the lattice. Investigation of these ordered phases sheds crucial light on the superconductivity itself. Here we report a low-temperature scanning tunneling microscopy (STM) study on RbFe2As2, a heavily hole-doped Fe-based superconductor (FeSC). We observe significant symmetry breaking in its electronic structure and magnetic vortex which differentiates the ({\pi}, {\pi}) and ({\pi}, -{\pi}) directions of the unfolded Brillouin zone (BZ). It is thus a novel nematic state, distinct from the nematicity of undoped/lightly-doped FeSCs which breaks the ({\pi}, 0) / (0, {\pi}) equivalence. Moreover, we observe a clear "V"-shaped superconducting gap which can be well fitted with a nodal gap function. The gap is found to be suppressed on surface Rb vacancies and at step edges, and the suppression is particularly strong at the [110]-oriented edges. This is possibly due to a dx2-y2 like pairing component with nodes along the [110] directions. We further demonstrated that such ({\pi}, {\pi}) nematic state can be suppressed via surface electron doping to RbFe2As2, and the superconductivity is subsequently enhanced. Our results thus highlight the intimate connection between nematicity and superconducting pairing in iron-based superconductors. Comment: 19 pages, 7 figures, supplementary materials included |
| Databáze: | OpenAIRE |
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