Effects of nanoscale spatial inhomogeneity in strongly correlated systems

Abstract

We calculate ground-state energies and density distributions of Hubbard superlattices characterized by periodic modulations of the on-site interaction and the on-site potential. Both density-matrix renormalization group and density-functional methods are employed and compared. We find that small variations in the on-site potential ν i can simulate, cancel, or even overcompensate effects due to much larger variations in the on-site interaction U i. Our findings highlight the importance of nanoscale spatial inhomogeneity in strongly correlated systems, and call for a reexamination of model calculations assuming spatial homogeneity. ©2005 The American Physical Society.