Non-linear density functional theory: A direct method to calculate many-electron charge densities

摘要

We suggest to include the density of electron charge explicitly in theelectron potential of density functional theory, rather than implicitly viaexchange-correlation functionals. The advantages of the approach are conceptualand numerical. Conceptually, it allows to formulate a physical principle forthe development of quantum mechanical systems: it is the principle of energeticequilibrium, because the energy principle, in this case, applies not onlyglobally, but also on a local level. The method is an order-$N$ method, scalinglinearly with the number of atoms. It is used to calculate the electronicgroundstate of a metallic surface, where we find good agreement withexperimental values.