Spatial spin-spin correlations of the single-impurity Anderson model with a ferromagnetic bath

TL;DR

This study explores how ferromagnetism influences the Kondo effect in a one-dimensional Anderson impurity model, revealing oscillations in spin correlations and a boundary between Kondo screening and bath polarization.

Contribution

It introduces a detailed analysis of spin-spin correlations in a polarized bath, including a fitting formula and identification of a boundary in the Kondo cloud behavior.

Findings

Oscillations in SSCF due to spin-split Fermi surfaces.

A fitting formula accurately describes SSCF across regions.

Identification of a boundary between Kondo cloud and polarized bath.

Abstract

We investigate the interplay between the Kondo effect and the ferromagnetism by an one dimension Anderson impurity model with a spin partially polarized bath, using the projective truncation approximation under Lacroix basis.The equal-time spatial spin-spin correlation function (SSCF) is calculated. For the case of spin-unpolarized conduction electrons, it agrees qualitatively with the results from density matrix renormalization group (DMRG). For system with partially spin-polarized conduction electrons, an oscillation in the envelope of SSCF emerges due to the beating of two Friedel oscillations associated to two spin-split Fermi surfaces of conduction electrons. The period is proportional to the inverse of magnetic field $h$. A fitting formula is proposed to perfectly fits the numerical results of SSCF in both the short- and long-range regions. For large enough bath spin polarization, a bump appears in the curve of the integrated SSCF. It marks the boundary between the suppressed Kondo cloud and the polarized bath sites.