Nanograin ferromagnets from nonmagnetic bulk materials: The case of gold nanoclusters

Abstract

The ferromagnetism of Au nanograins is analyzed based on a two-dimensional itinerant lattice model with on-site Coulomb repulsion, many-body spin–orbit interactions, and holding two hybridized bands, one correlated and one uncorrelated. Using periodic boundary conditions in both directions, an exact ferromagnetic ground state is deduced for this non-integrable system by applying special techniques based on positive semidefinite operators.