Appearance of Universal Metallic Dispersion in a Doped Mott Insulator

TL;DR

This study reveals that doped Mott insulators exhibit a universal metallic dispersion with a renormalization factor approaching unity near the Mott transition, indicating preformed metallic states within the insulating phase.

Contribution

It demonstrates the emergence of LDA-like dispersion and metallic states in doped cuprates across a wide doping range, challenging existing theories.

Findings

Dispersion renormalization approaches unity near the Mott insulator

Presence of preformed metallic states within the insulating phase

Universal metallic dispersion observed across doping levels

Abstract

We have investigated the dispersion renormalization $Z_{disp}$ in La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) over the wide doping range of $x=0.03-0.30$, for binding energies extending to several hundred meV's. Strong correlation effects conspire in such a way that the system exhibits an LDA-like dispersion which essentially `undresses' ($Z_{disp}\to 1$) as the Mott insulator is approached. Our finding that the Mott insulator contains `nascent' or `preformed' metallic states with a vanishing spectral weight offers a challenge to existing theoretical scenarios for cuprates.