Electronic transport through quantum dots coupled to ferromagnetic leads: from Coulomb blockade to Kondo effect

We present a short review on electron transport in strongly correlated nanostructures, quantum dots in particular. We describe briefly the main correlation effects, namely the Coulomb blockade and Kondo effect, and introduce three widely used numerical techniques to study these effects. We then give a brief summary of some more elaborate set-ups where two or more effects compete, making the transport properties very interesting to study. In particular, we report the cases of multilevel quantum dots, carbon nanotube based quantum dots, and quantum dots coupled by RKKY interaction.

Download Full-text

Spin Polarized Transport through Quantum Dots: Coulomb Blockade and Kondo Effect

Acta Physica Polonica A ◽

10.12693/aphyspola.104.165 ◽

2003 ◽

Vol 104 (2) ◽

pp. 165-177

Author(s):

J. Barnaś ◽

R. Świrkowicz ◽

M. Wilczyński ◽

I. Weymann ◽

J. Martinek ◽

...

Keyword(s):

Quantum Dots ◽

Coulomb Blockade ◽

Kondo Effect ◽

Spin Polarized ◽

Polarized Transport ◽

Spin Polarized Transport

Download Full-text

Non-equilibrium Kondo Effect in Electronic Transport through Quantum Dots

Czechoslovak Journal of Physics ◽

10.1007/s10582-004-0156-6 ◽

2004 ◽

Vol 54 (S4) ◽

pp. 615-618 ◽

Cited By ~ 2

Author(s):

R. Świrkowicz ◽

M. Wilczyński ◽

J. Barnaś

Keyword(s):

Quantum Dots ◽

Electronic Transport ◽

Kondo Effect ◽

Non Equilibrium

Download Full-text

Nonequilibrium Kondo effect in a graphene-coupled quantum dot in the presence of a magnetic field

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.11.17 ◽

2020 ◽

Vol 11 ◽

pp. 225-239

Author(s):

Levente Máthé ◽

Ioan Grosu

Keyword(s):

Magnetic Field ◽

Quantum Dots ◽

Quantum Dot ◽

Coulomb Interaction ◽

Coulomb Blockade ◽

Kondo Effect ◽

Dirac Point ◽

Analytical Formula ◽

Kondo Temperature ◽

Hole Doping

Background: Quantum dots connected to larger systems containing a continuum of states like charge reservoirs allow the theoretical study of many-body effects such as the Coulomb blockade and the Kondo effect. Results: Here, we analyze the nonequilibrium Kondo effect and transport phenomena in a quantum dot coupled to pure monolayer graphene electrodes under external magnetic fields for finite on-site Coulomb interaction. The system is described by the pseudogap Anderson Hamiltonian. We use the equation of motion technique to determine the retarded Green’s function of the quantum dot. An analytical formula for the Kondo temperature is derived for electron and hole doping of the graphene leads. The Kondo temperature vanishes in the vicinity of the particle–hole symmetry point and at the Dirac point. In the case of particle–hole asymmetry, the Kondo temperature has a finite value even at the Dirac point. The influence of the on-site Coulomb interaction and the magnetic field on the transport properties of the system shows a tendency similar to the previous results obtained for quantum dots connected to metallic electrodes. Most remarkably, we find that the Kondo resonance does not show up in the density of states and in the differential conductance for zero chemical potential due to the linear energy dispersion of graphene. An analytical method to calculate self-energies is also developed which can be useful in the study of graphene-based systems. Conclusion: Our graphene-based quantum dot system provides a platform for potential applications of nanoelectronics. Furthermore, we also propose an experimental setup for performing measurements in order to verify our model.

Download Full-text

Coulomb blockade and Kondo effect in quantum dots

New Directions in Mesoscopic Physics (Towards Nanoscience) ◽

10.1007/978-94-007-1021-4_4 ◽

2003 ◽

pp. 93-115 ◽

Cited By ~ 3

Author(s):

L. I. Glazman ◽

M. Pustilnik

Keyword(s):

Quantum Dots ◽

Coulomb Blockade ◽

Kondo Effect

Download Full-text

Transport in Multilevel Quantum Dots: From the Kondo Effect to the Coulomb Blockade Regime

Physical Review Letters ◽

10.1103/physrevlett.83.600 ◽

1999 ◽

Vol 83 (3) ◽

pp. 600-603 ◽

Cited By ~ 64

Author(s):

A. Levy Yeyati ◽

F. Flores ◽

A. Martín-Rodero

Keyword(s):

Quantum Dots ◽

Coulomb Blockade ◽

Kondo Effect ◽

Coulomb Blockade Regime

Download Full-text

Imaging the electrostatic landscape of unstrained self-assemble GaAs quantum dots

Nanotechnology ◽

10.1088/1361-6528/ac47ce ◽

2022 ◽

Author(s):

Evandro Martin Lanzoni ◽

Saimon Covre da Silva ◽

Floris Knopper ◽

Ailton J Garcia ◽

Carlos Alberto Rodrigues Costa ◽

...

Keyword(s):

Quantum Dots ◽

Surface Potential ◽

Coulomb Blockade ◽

Kondo Effect ◽

Lower Surface ◽

Electrical Signal ◽

Kelvin Probe ◽

Force Microscopy ◽

Fermi Level Pinning ◽

Physical Phenomena

Abstract Unstrained GaAs quantum dots are promising candidates for quantum information devices due to their optical properties, but their electronic properties have remained relatively unexplored until now. In this work, we systematically investigate the electronic structure and natural charging of GaAs quantum dots at room temperature using Kelvin probe force microscopy (KPFM). We observe a clear electrical signal from structures demonstrating a lower surface potential in the middle of the dot. We ascribe this to charge accumulation and conﬁnement inside these structures. Our systematical investigation reveals that the change in surface potential is larger for a nominal dot ﬁlling of 2 nm and then starts to decrease for thicker GaAs layers. Using k . p calculation, we show that the conﬁnement comes from the band banding due to the surface Fermi level pinning. Our results indicate that these self-assembled structures could be used to study physical phenomena connected to charged quantum dots like Coulomb blockade or Kondo eﬀect.

Download Full-text