Appearance of universal metallic dispersion in a doped Mott insulator

Abstract

We have investigated the dispersion renormalization Zdisp in La2-x Srx CuO4 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 a local-density-approximation-like dispersion which essentially "undresses" (Zdisp →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. © 2008 The American Physical Society.