Resonant Impurity Scattering in a Strongly Correlated Electron Model

TL;DR

This paper investigates how a non-magnetic impurity causes resonant scattering in a strongly correlated electron system, revealing bound states with different symmetries as the antiferromagnetic coupling increases.

Contribution

It demonstrates that inert, spinless impurities induce strong resonant scattering and bound states in a correlated electron model, using exact diagonalization methods.

Findings

Inert impurity sites cause resonant scattering in the model.

Bound states with d, s, and p-wave symmetry emerge with increasing antiferromagnetic coupling.

Local density of states calculations show the trapping of mobile holes by impurity-induced distortions.

Abstract

Scattering by a single impurity introduced in a strongly correlated electronic system is studied by exact diagonalization of small clusters. It is shown that an inert site which is spinless and unable to accomodate holes can give rise to strong resonant scattering. A calculation of the local density of state reveals that, for increasing antiferromagnetic exchange coupling, d, s and p-wave symmetry bound states in which a mobile hole is trapped by the impurity potential induced by a local distortion of the antiferromagnetic background successively pull out from the continuum.