Electron-hole asymmetry in electron systems with orbital degeneracy and correlated hopping

TL;DR

This paper develops a microscopic model for orbital-degenerate electron systems with correlated hopping, deriving equations for doublon concentration and analyzing how correlated hopping influences the transition from itinerant to localized electronic behavior.

Contribution

It introduces a configuration-operator approach to model orbital degeneracy with correlated hopping and derives equations for doublon concentration at various densities and temperature regimes.

Findings

Derived equations for doublon concentration at different densities and temperatures.

Analyzed the impact of correlated hopping on electronic transition behavior.

Discussed energy spectra in relation to correlated hopping effects.

Abstract

Microscopic models of electronic subsystems with orbital degeneracy of energy states and non-diagonal matrix elements of electron interactions (correlated hopping) are considered within the configuration-operator approach. Equations for arbitrary-temperature numerical calculation of the doublon concentration for the integer band filling $n=1$ at different forms of the model density of states are derived. The energy spectra obtained within the Green function method are discussed with special emphasis on the role of correlated hopping in transition from itinerant to localized behavior observed in vanadium Magneli phases V$_n$O$_{2n-1}$, transition-metal dichalcogenides NiS$_{2-x}$Se$_x$, fulleride A$_n$C$_{60}$ systems.