Quantum dot with ferromagnetic leads: a density-matrix renormalization group study

TL;DR

This study uses the density matrix renormalization group method to analyze a quantum dot connected to ferromagnetic leads, revealing how lead polarization affects the local density of states, Kondo cloud, and tunnel magnetoresistance.

Contribution

It provides a detailed numerical analysis of the effects of ferromagnetic lead polarization on quantum dot properties using the DMRG method, including the Kondo cloud and magnetoresistance behavior.

Findings

Local density of states is suppressed by parallel lead polarization.

Estimated the length of the Kondo cloud and its relation to suppression.

Tunnel magnetoresistance is minimum and negative at the symmetric point.

Abstract

A quantum dot coupled to ferromagnetically polarized one-dimensional leads is studied numerically using the density matrix renormalization group method. Several real space properties and the local density of states at the dot are computed. It is shown that this local density of states is suppressed by the parallel polarization of the leads. In this case we are able to estimate the length of the Kondo cloud, and to relate its behavior to that suppression. Another important result of our study is that the tunnel magnetoresistance as a function of the quantum dot on-site energy is minimum and negative at the symmetric point.