2018/05/24 by M. S. Laad, Byron Freelon, Laad, Mukul S. +3
Business, Management and Accounting · Materials Science · #Corporate Finance and Governance #Corporate Taxation and Avoidance #FOS: Physical sciences #Iron-based superconductors research #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.1805.09628
openalex publication_date 2018/05/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Finding of unconventional superconductivity (USC) in FeSe in an electronic "normal" state with broken C4v rotational symmetry testifies to the diversity of pairing states in Fe-based superconductors. Moreover, such USC emerges as a direct instability of a normal state without Landau Fermi liquid quasiparticles, increasingly dubbed a `strange' metal. Here, we combine inputs from a first-principles correlated electronic structure method (LDA+DMFT) and symmetry analyses to propose a novel mechanism for unconventional nodal superconductivity as a direct instability of an incoherent bad-metal without Landau Fermi-liquid quasiparticles. We find that a ferro-quadrupolar order, with novel spin quadrupoar correlations enhances orbital-selective Mottness in FeSe, and competes with unconventional nodal superconductivity with s±-pair symmetry. We support our proposal by demonstrating good accord with spectral and magnetic fluctuation data, and rationalize the strain and pressure dependence of Tc by appealing to competition between superconductivity and electronic ferro-quadrupolar order.