Spin magnetization of strongly correlated electron gas confined in a two-dimensional finite lattice

TL;DR

This study investigates how disorder and electron interactions influence the spin polarization of a 2D correlated electron gas in a finite lattice, revealing conditions for ferromagnetic ground states and the effects of localization.

Contribution

It provides numerical analysis of the ground state polarization considering disorder and interactions, highlighting the conditions for ferromagnetism in finite 2D systems.

Findings

Ferromagnetic ground state plausible at low electron numbers and specific parameters.

Disorder-induced spin polarization is suppressed when electrons become strongly localized.

Interaction matrix fluctuations favor ferromagnetic instability in extended and weak localization regimes.

Abstract

The influence of disorder and interaction on the ground state polarization of the two-dimensional (2D) correlated electron gas is studied by numerical investigations of unrestricted Hartree-Fock equations. The ferromagnetic ground state is found to be plausible when the electron number is lowered and the interaction and disorder parameters are suitably chosen. For a finite system at constant electronic density the disorder induced spin polarization is cut off when the electron orbitals become strongly localized to the individual network sites. The fluctuations of the interaction matrix elements are calculated and brought out as favoring the ferromagnetic instability in the extended and weak localization regime. The localization effect of the Hubbard interaction term is discussed.