Binding of Holes to Magnetic Impurities in a Strongly Correlated System
arXiv:cond-mat/9404092 · doi:10.1103/PhysRevB.50.13020
Abstract
The effect of a magnetic (S=1/2) impurity coupled to a 2D system of correlated electrons (described by the t--J model) is studied by exact diagonalisations. It is found that, if the exchange coupling of the impurity with the neighboring spins is ferromagnetic or weakly antiferromagnetic, an extra hole can form bound states of different spatial symmetries with the impurity extending to a few lattice spacings. The binding energy is maximum when the impurity is completely decoupled (vacancy) and vanishes for an antiferromagnetic coupling exceeding $\sim 0.3 J$. Several peaks appear in the single hole spectral function below the lower edge of the quasiparticle band as signatures of the d-, s- and p-wave boundstates.
Latex 11 pages, postscript files in uuencoded form, report# LPQTH-94/6