Theory of carrier concentration-dependent electronic behavior in layered cobaltates

TL;DR

This paper explains how carrier concentration influences electronic behavior in layered cobaltates using correlated-electron Hamiltonians with Coulomb interactions, revealing how hole occupancy varies with doping levels.

Contribution

It introduces a theoretical framework showing the impact of nearest neighbor Coulomb repulsions on hole occupancy and electronic properties in layered cobaltates, applicable to multiple Hubbard models.

Findings

Nearest neighbor repulsion reduces hole double-occupancy below 1/3 doping.

At higher hole densities, repulsion increases hole double-occupancy.

Results apply to both single-band and three-band Hubbard Hamiltonians.

Abstract

A natural explanation for the carrier concentration-dependent electronic behavior in the layered cobaltates emerges within correlated-electron Hamiltonians with finite on-site and significant nearest neighbor hole-hole Coulomb repulsions. The nearest neighbor repulsion decreases hole double-occupancy below hole density 1/3, but increases the same at higher hole densities. Our conclusion is valid for both single-band and three-band extended Hubbard Hamiltonians, and sheds light on concentration-dependent $e_g^\prime$ hole occupancy within the latter.