Pressure-induced orbital-selective metal from the Mott insulator BaFe2Se3

Abstract

A general understanding of the mechanism underlying the pressure-induced Mott insulator-metal transition in strongly correlated materials is still lacking. Here we explore the pressure-induced electronic reconstruction in BaFe 2 Se 3 , a potential two-leg ladder system for unconventional (non-BCS) superconductivity. We stress the importance of multiorbital Coulomb interactions in concert with first-principles band-structure calculations for a consistent understanding of its intrinsic Mott-Hubbard insulating state both at ambient and under pressure. We elucidate the nature of pressure-induced insulator-metal transition seen in experiment, showing that it is driven by bandwidth broadening under pressure. We reveal an orbital-selective electronic state where Mott localized and itinerant electrons coexist in compressed BaFe 2 Se 3 , which incorporates orbital-resolved scattering rates and renormalization factors hidden in the normal state at high pressures.