2021/03/31 by Fabian Schrodi, Fairoja Cheenicode Kabeer, Alex Aperis +1
Business, Management and Accounting · Materials Science · Physics and Astronomy · #Ab initio #Band gap #Charge (physics) #Condensed matter physics #Cooper pair #Electron #Fermi surface #Frustration #Graph #Intellectual Capital and Performance Analysis #Iron-based superconductors research #Physics #Quantum mechanics #Rare-earth and actinide compounds #Spin (aerodynamics) #Superconductivity #Vertex (graph theory) #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.104.094516
published in Physical review. B./Physical review. B 104(9) (American Physical Society)
arxiv created 2021/03/31 · openalex publication_date 2021/09/16 · arxiv updated 2021/09/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We investigate theoretically the superconducting state of the undoped Fe-based superconductor ThFeAsN. Using input from ab initio calculations, we solve the Fermi-surface based, multichannel Eliashberg equations for Cooper-pair formation mediated by spin and charge fluctuations, and by the electron-phonon interaction (EPI). Our results reveal that spin fluctuations alone, when coupling only hole-like with electron-like energy bands, can account for a critical temperature Tc up to \ensuremath∼7.5\phantom\rule0.16em0exK with an s_\ifmmode±\else\textpm\fi-wave superconducting gap symmetry, which is a comparatively low Tc with respect to the experimental value Tcexp=30\phantom\rule0.16em0exK. Other combinations of interaction kernels (spin, charge, electron-phonon) lead to a suppression of Tc due to phase frustration of the superconducting gap. We qualitatively argue that the missing ingredient to explain the gap magnitude and Tc in this material might be the first-order correction to the EPI vertex. In the noninteracting state this correction adopts a form supporting the s_\ifmmode±\else\textpm\fi gap symmetry, in contrast to EPI within Migdal's approximation, i.e., EPI without vertex correction, and therefore it enhances tendencies arising from spin fluctuations.