Exploring multichannel superconductivity in ThFeAsN
| Autor: | Alex Aperis, Peter M. Oppeneer, Fabian Schrodi, Fairoja Cheenicode Kabeer |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Superconductivity
Physics Condensed matter physics media_common.quotation_subject Condensed Matter - Superconductivity Frustration FOS: Physical sciences Charge (physics) Coupling (probability) Condensed Matter Physics Vertex (geometry) Superconductivity (cond-mat.supr-con) Ab initio quantum chemistry methods Condensed Matter::Superconductivity Condensed Matter::Strongly Correlated Electrons Den kondenserade materiens fysik Energy (signal processing) media_common Spin-½ |
| Popis: | 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 ${T}_{c}$ up to $\ensuremath{\sim}7.5\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ with an ${s}_{\ifmmode\pm\else\textpm\fi{}}$-wave superconducting gap symmetry, which is a comparatively low ${T}_{c}$ with respect to the experimental value ${T}_{c}^{\mathrm{exp}}=30\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. Other combinations of interaction kernels (spin, charge, electron-phonon) lead to a suppression of ${T}_{c}$ due to phase frustration of the superconducting gap. We qualitatively argue that the missing ingredient to explain the gap magnitude and ${T}_{c}$ in this material might be the first-order correction to the EPI vertex. In the noninteracting state this correction adopts a form supporting the ${s}_{\ifmmode\pm\else\textpm\fi{}}$ 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|