Charge-density waves in one-dimensional Hubbard superlattices

摘要

We study the formation of charge density waves (CDW's) in one-dimensionalHubbard superlattices, modeled by a repeated pattern of repulsive (U>0) andfree (U=0) sites. By means of Lanczos diagonalizations for the ground state, wecalculate the charge structure factor. Our results show that while thesuperlattice structure affects the modulation of the charge density waves, theperiodicity can still be predicted through an effective density. We also showthat, for a fixed repulsive layer thickness, the periodicity of the CDW is anoscillatory function of the free layer thickness.