The action of the nearest neighbor Coulomb repulsion on the homogeneity in the high concentration domain for itinerant systems

TL;DR

This paper presents exact results showing that nearest neighbor Coulomb repulsion causes inhomogeneity in high concentration itinerant systems, highlighting the complex role of V in phase behavior.

Contribution

It provides the first exact analysis of how nearest neighbor Coulomb repulsion affects homogeneity in high concentration regimes of itinerant systems.

Findings

V destroys homogeneity at high concentrations

Effects of V are related to its intrinsic properties, not just phase characteristics

Ground states are connected to non-integrable systems

Abstract

Exact results are presented for itinerant systems demonstrating that the nearest neighbor Coulomb repulsion (V) destroys the homogeneity in the high concentration regime, this property being not present in the low concentration domain. Since the effects of V often seems contradictory, and the number of phases in which it could appear is extremely large, this result underlines that the action of the nearest neighbor repulsion is not necessarily routed in the characteristics of phases on which it acts, but could be intimately related to V itself. The $V > 0$ case usually means non-integrability, hence the deduced exact ground states are related to non-integrable systems, the technique being based on positive semidefinite operator properties.