Magnetic and transport properties of the one-dimensional ferromagnetic Kondo lattice model with an impurity

TL;DR

This study investigates the magnetic and transport properties of a one-dimensional ferromagnetic Kondo lattice model with an impurity, revealing a singlet phase between ferromagnetic states and providing insights relevant for nanoscopic device experiments.

Contribution

It introduces a numerical analysis of the FKLM with an Anderson impurity, identifying a novel singlet phase and exploring transport behavior in this context.

Findings

Identification of a singlet phase between ferromagnetic states.

Transport properties vary with impurity occupancy as expected.

Results applicable to nanoscopic devices and impurity-doped MnO nanotubes.

Abstract

We have studied the ferromagnetic Kondo lattice model (FKLM) with an Anderson impurity on finite chains with numerical techniques. We are particularly interested in the metallic ferromagnetic phase of the FKLM. This model could describe either a quantum dot coupled to one-dimensional ferromagnetic leads made with manganites or a substitutional transition metal impurity in a MnO chain. We determined the region in parameter space where the impurity is empty, half-filled or doubly-occupied and hence where it is magnetic or nonmagnetic. The most important result is that we found, for a wide range of impurity parameters and electron densities where the impurity is magnetic, a singlet phase located between two saturated ferromagnetic phases which correspond approximately to the empty and double-occupied impurity states. Transport properties behave in general as expected as a function of the impurity occupancy and they provide a test for a recently developed numerical approach to compute the conductance. The results obtained could be in principle reproduced experimentally in already existent related nanoscopic devices or in impurity doped MnO nanotubes.