Structure-dependent metal–insulator transition in one-dimensional Hubbard superlattice

Abstract

We investigate the charge and spin gaps, and the spin structure in half-filled one-dimensional Hubbard superlattices with one repulsive site and L0 free sites per unit cell. For odd L0, it is correlated metal at the particle–hole symmetric point, and then turns into band insulator beyond this point. For even L0, the system has a Mott insulator phase around the particle–hole symmetric point and undergoes a metal–insulator transition with on-site repulsion U increasing. For large U, there exists a multiperiodic spin structure, which results from the ferromagnetic (antiferromagnetic) correlation between the nearest neighboring repulsive sites for odd (even) L0.

Giant Magnetoresistance in Hubbard Chains

“…Model and methods. -We use the one-dimensional Hubbard model with site-dependent interactions [9][10][11][12][13][14], creating a superlattice of size L,…”