Hund’s correlated Metals

Abstract

Metallic phases with Hund’s correlations (“Hund’s metals”) are presently the focus of intensive research, in particular in relation to unconventional Fe-based superconductors. Recent experiments validate this emerging theoretical picture of a metallic phase with evidences of large local paramagnetic moments, large and orbital-selective mass renormalizations and orbitallyselective pairing in the superconducting state. Further theoretical insight shows that Hund’s coupling can also alter the quasiparticle interactions in some regimes, thus potentially renormalizing the pairing strength. This is shown to correlate with experimental high-Tc superconductivity in Fe-based pnictides and FeSe. Additionally, specular many-body physics is predicted for Cr-based analogues of these materials, possibly indicating a new playground where high-Tc superconductors might be found. L. de’ Medici, Phys. Rev. Lett. 118, 167003 (2017) P. Villar-Arribi and L. de’ Medici, ArXiv:1803.01494 (2018) Edelmann et al. PRB 95, 205118 (2017)