Friedel oscillations induced by non-magnetic impurities in the two-dimensional Hubbard model

TL;DR

This paper investigates how non-magnetic impurities induce Friedel oscillations in the charge density of the two-dimensional Hubbard model, revealing the effects of interactions on these oscillations and local magnetic moments.

Contribution

It introduces an unrestricted Slave-Boson approach to analyze impurity-induced oscillations and magnetic states in the Hubbard model, providing new insights into correlation effects.

Findings

Friedel oscillations are observed near impurities, consistent with numerical simulations.

Repulsive interactions suppress oscillation amplitudes, attractive interactions enhance charge-density waves.

Local magnetic moments can form at impurity sites depending on interaction strength.

Abstract

We study the interplay of correlations and disorder using an unrestricted Slave-Boson technique in real space. Within the saddle-point approximation, we find Friedel oscillations of the charge density in the vicinity of a nonmagnetic impurity, in agreement with numerical simulations. The corresponding amplitudes are suppressed by repulsive interactions, while attractive correlations lead to a charge-density-wave enhancement. In addition, we investigate the spatial dependence of the local magnetic moment and the formation of a magnetic state at the impurity site.