2012/09/30 by Maxim Khodas, M. Khodas, Andrey V. Chubukov +1
Business, Management and Accounting · Materials Science · Physics and Astronomy · #Corporate Taxation and Avoidance #Iron-based superconductors research #Physics of Superconductivity and Magnetism #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.86.144519
published as Phys. Rev. B 86, 144519 (2012) · 16 pages, 13 figures. References reordered, typos corrected
arxiv created 2012/10/10 · openalex publication_date 2012/10/17 · arxiv updated 2012/10/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We consider Fe-based superconductors with s^+\ensuremath- gap with accidental nodes on electron pockets. We analyze how the gap structure changes if we include into the consideration the hybridization between the two electron pockets [the interpocket hopping term with momentum (\ensuremathπ,\ensuremathπ,\ensuremathπ)]. We derive the hybridization term and relate it to the absence of inversion symmetry in the Fe plane because of two nonequivalent locations of pnictogen (chalcogen) above and below the plane. We find that the hybridization tends to eliminate the nodes---as it increases, the pairs of neighboring nodes approach each other, merge, and disappear once the hybridization exceeds a certain threshold. The nodes disappear first around kz=\ensuremathπ/2, and vertical line nodes split into two vertical loops centered at kz=0 and kz=\ensuremathπ. We also show that the hybridization moves the nodes along the loops away from the normal-state Fermi surfaces. This creates a subset of k points at which the peak in the spectral function does not shift as the system enters into a superconducting state (``no-shift'' lines). These no-shift lines evolve with increasing hybridization in a highly nontrivial manner and eventually form horizontal loops in the (kx,ky) plane, surrounding the nodes. Both vertical line nodes and horizontal no-shift loops surrounding them should be detectable in photoemission experiments.