Pnictogen height as a possible switch between high- T c nodeless and low- T c nodal pairings in the iron-based superconductors
By K. Kuroki, H. Usui, S. Onari, Ryotaro Arita, H. Aoki. 2009
433 citations recorded by the source corpus.
We study the effect of the lattice structure on the spin-fluctuation-mediated superconductivity in the iron pnictides adopting the five-band models of several virtual lattice structures of LaFeAsO, as well as actual materials such as NdFeAsO and LaFePO obtained from the maximally localized Wannier orbitals. Random phase approximation is applied to the models to solve the Eliashberg equation. This reveals that the gap function and the strength of the superconducting instability are determined by the cooperation or competition among multiple spin-fluctuation modes arising from several nestings among disconnected pieces of the Fermi surface, which is affected by the lattice structure. Specifically, the appearance of the Fermi surface $\ensuremath{\gamma}$ around $(\ensuremath{\pi},\ensuremath{\pi})$ in the unfolded Brillouin zone is sensitive to the pnictogen height ${h}_{\text{Pn}}$ measured from the Fe plane, where ${h}_{\text{Pn}}$ is shown to act as a switch between high-${T}_{c}$ nodeless and low-${T}_{c}$ nodal pairings. We also find that reduction in the lattice constants generally suppresses superconductivity. We can then combine these to obtain a generic superconducting phase diagram against the pnictogen height and lattice constant. This suggests that NdFeAsO is expected to exhibit a fully gapped, sign-reversing $s$-wave superconductivity with a higher ${T}_{c}$ than in LaFeAsO, while a nodal pairing with a low ${T}_{c}$ is expected for LaFePO, which is consistent with experiments.
Subfields: Accounting, Electronic, Optical and Magnetic Materials
View Paper: https://www.semanticscholar.org/paper/98d29271f66393f3c2e6fb19a2952d0e99bd5782
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In Electronic, Optical and Magnetic Materials
Citations in the corpus
- High-temperature superconductivity in iron-based materials (2010, background): “BZ, and its presence may be very sensitive to structural details [33].”
- Superconductivity in iron compounds (2011, background): “They discussed this difference in pressure effect as being due to the height of the pnictogen, as discussed in the theory of Kuroki et al. (2009) in Sec.”
- Iron-based high transition temperature superconductors (2014, background): “[202] Kuroki, K, Usui, H and Onari, S et al.”