Ground-state phase diagram and magnetoconductance of a one-dimensional Hubbard superlattice at half filling

Abstract

We have studied a one dimensional Hubbard superlattice with different Coulomb correlations at alternating sites for a half-filled band. Mean field calculations based on the Hartree-Fock approximation together with a real space renormalization group technique were used to study the ground state of the system. The phase diagrams obtained in these approaches agree with each other from the weak to the intermediate coupling regime. The mean field results show very quick convergence with system size. The renormalization group results indicate a spatial modulation of local moments that was identified in some previous work. Also we have studied the magnetoconductance of such superlattices which reveals several interesting points.

Mobility edge phenomenon in a Hubbard chain: A mean field study

“…Furthermore, a superlattice structure comprising sites on which electron-electron interactions are expressed differently (some sites are interacting and some sites are non-interacting) is characterized by multiple occurrence of mobility edges at several values of the carrier energy. The applicability of mean field approximation in such superlattice geometries has already been reported in a recent work 24 .…”

Magnetism, transport, and thermodynamics in two-dimensional half-filled Hubbard superlattices

“…The ground-state magnetic and transport properties of the site-dependent Hubbard model have been extensively studied in one-dimension. The non-symmetric Hamiltonian was studied with different numerical approaches, such as the Lanczos method [23][24][25], density matrix renormalization group [26], within the Hartree-Fock approximation [27], and within the Luttinger liquid framework [28]. The effect of an on-site energy in one of the sublattices was also considered [29,30] and was shown to strongly alter the ground state properties.…”

Effect of external electric field on the charge density waves in one-dimensional Hubbard superlattices

“…Now we discuss the results for the −0 − U − superlattice structure. At half-filling the system is a CDW insulator with q = π in the absence of electric field [5,7] and the charge gap is finite (V = 0 case in Fig. 3(a)).…”

“…This form of the site potential is used to ensure that the external bias varies from −V /2 to V /2 across the superlattice. We will work in the weak to intermediate coupling regime where U < ∼ t. It was observed in a previous work that in this regime the mean field approximation is quite reliable for this class of systems [7].…”