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Superconductivity without hole-pocket in electron-doped FeSe: Analysis beyond the Migdal-Eliashberg formalism
- Publication Year :
- 2016
- Publisher :
- arXiv, 2016.
-
Abstract
- High-Tc pairing mechanism absent of hole-pockets in heavily electron-doped FeSe is one of the key unsolved problems in Fe-based superconductors. Here, this problem is attacked by focusing on the higher-order many-body effects neglected in conventional Migdal-Eliashberg formalism. We uncover two significant many-body effects for high-Tc superconductivity: (i) Due to the "vertex correction", the dressed multiorbital Coulomb interaction acquires prominent orbital dependence for low-energy electrons. The dressed Coulomb interaction not only induces the orbital fluctuations, but also magnifies the electron-boson coupling constant. Therefore, moderate orbital fluctuations give strong attractive pairing interaction. (ii) The "multi-fluctuation-exchange pairing process" causes large inter-pocket attractive force, which is as important as usual single-fluctuation-exchange process. Due to these two significant effects dropped in the Migdal-Eliashberg formalism, the anisotropic $s_{++}$-wave state in heavily electron-doped FeSe is satisfactorily explained. The proposed "inter-electron-pocket pairing mechanism" will enlarge Tc in other Fe-based superconductors.<br />Comment: 12 pages, 10 figures
- Subjects :
- Physics
Superconductivity
Coupling constant
Condensed matter physics
Strongly Correlated Electrons (cond-mat.str-el)
Condensed Matter - Superconductivity
FOS: Physical sciences
02 engineering and technology
Electron
Electron doped
021001 nanoscience & nanotechnology
01 natural sciences
Superconductivity (cond-mat.supr-con)
Condensed Matter - Strongly Correlated Electrons
Formalism (philosophy of mathematics)
Pairing
Quantum mechanics
Condensed Matter::Superconductivity
0103 physical sciences
Coulomb
010306 general physics
0210 nano-technology
Anisotropy
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....2cd87276f421ddb6dbba1ea66fae7bd9
- Full Text :
- https://doi.org/10.48550/arxiv.1611.05375