Impurity scattering in a strongly correlated host

Abstract

This work explores a simple approximation to describe isolated impurity scattering in a strongly correlated host. The approximation combines conventional one-electron scattering theory and the Dynamic Mean-Field Theory to describe strong correlations in the host. It becomes exact in several limits, including those of very strong interactions. We study the problem for a large range of parameter strengths and focus on the case of a strongly correlated metal host near the Mott metal-insulator transition. We find interesting effects on the electronic structure at the impurity site with the appearence of bound states at frequencies that are strongly renormalized from the bare impurity potential value. However, the strength of the threshold potential for the onset of the bound states remains of the order of the bare host bandwidth, i.e. essentially unrenormalized with respect to the non-interacting case. Our results may provide useful guidance for interpretation of scanning tunneling microscopy experiments in strongly correlated systems. © Europhysics Letters Association.