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Title: Tunnel magnetoresistance and linear conductance of double quantum dots strongly coupled to ferromagnetic leads

Abstract

We analyze the spin-dependent linear-response transport properties of double quantum dots strongly coupled to external ferromagnetic leads. By using the numerical renormalization group method, we determine the dependence of the linear conductance and tunnel magnetoresistance on the degree of spin polarization of the leads and the position of the double dot levels. We focus on the transport regime where the system exhibits the SU(4) Kondo effect. It is shown that the presence of ferromagnets generally leads the suppression of the linear conductance due to the presence of an exchange field. Moreover, the exchange field gives rise to a transition from the SU(4) to the orbital SU(2) Kondo effect. We also analyze the dependence of the tunnel magnetoresistance on the double dot levels' positions and show that it exhibits a very nontrivial behavior.

Authors:
 [1]
  1. Faculty of Physics, Adam Mickiewicz University, 61-614 Poznań (Poland)
Publication Date:
OSTI Identifier:
22410091
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; FERROMAGNETIC MATERIALS; KONDO EFFECT; MAGNETORESISTANCE; QUANTUM DOTS; RENORMALIZATION; SPIN; SPIN ORIENTATION; SU-4 GROUPS; TUNNEL EFFECT

Citation Formats

Weymann, Ireneusz, E-mail: weymann@amu.edu.pl. Tunnel magnetoresistance and linear conductance of double quantum dots strongly coupled to ferromagnetic leads. United States: N. p., 2015. Web. doi:10.1063/1.4907329.
Weymann, Ireneusz, E-mail: weymann@amu.edu.pl. Tunnel magnetoresistance and linear conductance of double quantum dots strongly coupled to ferromagnetic leads. United States. doi:10.1063/1.4907329.
Weymann, Ireneusz, E-mail: weymann@amu.edu.pl. Thu . "Tunnel magnetoresistance and linear conductance of double quantum dots strongly coupled to ferromagnetic leads". United States. doi:10.1063/1.4907329.
@article{osti_22410091,
title = {Tunnel magnetoresistance and linear conductance of double quantum dots strongly coupled to ferromagnetic leads},
author = {Weymann, Ireneusz, E-mail: weymann@amu.edu.pl},
abstractNote = {We analyze the spin-dependent linear-response transport properties of double quantum dots strongly coupled to external ferromagnetic leads. By using the numerical renormalization group method, we determine the dependence of the linear conductance and tunnel magnetoresistance on the degree of spin polarization of the leads and the position of the double dot levels. We focus on the transport regime where the system exhibits the SU(4) Kondo effect. It is shown that the presence of ferromagnets generally leads the suppression of the linear conductance due to the presence of an exchange field. Moreover, the exchange field gives rise to a transition from the SU(4) to the orbital SU(2) Kondo effect. We also analyze the dependence of the tunnel magnetoresistance on the double dot levels' positions and show that it exhibits a very nontrivial behavior.},
doi = {10.1063/1.4907329},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 17,
volume = 117,
place = {United States},
year = {2015},
month = {5}
}