Nonequilibrium spin-current detection with a single Kondo impurity

Lim, Jong Soo; López, Rosa; Limot, L.; Simon, Pascal

doi:10.1103/physrevb.88.165403

Cited by 16 publications

(18 citation statements)

References 58 publications

(90 reference statements)

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“…One of the broadly used EOM techniques [6,7,10,11,16] is the decoupling scheme proposed by Lacroix [17]. This scheme was based on the Heisenberg equations of motion with differentiation over one time variable.…”

Section: Introductionmentioning

confidence: 99%

Alternative equation of motion approach applied to transport through a quantum dot

Górski

Mizia

Kucab

2015

Physica E: Low-dimensional Systems and Nanostructures

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-We study non-equilibrium electron transport through a quantum dot coupled to metallic leads. We use an alternative equation of motion approach in which we calculate the retarded Green function of the impurity by differentiating Green functions over both time variables. Such an approach allows us to obtain the resonance Kondo state in the particle-hole symmetric case and in the asymmetric cases. We apply this technique for calculating the density of the states of quantum dot and the differential conductance as a function of bias voltage. The differential conductance dependence on temperature and on Coulomb interaction is also calculated.

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Section: Introductionmentioning

confidence: 99%

Alternative equation of motion approach applied to transport through a quantum dot

Górski

Mizia

Kucab

2015

Physica E: Low-dimensional Systems and Nanostructures

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“…If the leads are magnetic, the Kondo resonance is perturbed by the exchange interaction in the leads [9], splitting the zero-bias anomaly in the differential conductance in both collinear [10] and noncollinear [11] orientations of the leads. It was, furthermore, theoretically shown that spin accumulation associated with a spin-dependent bias also splits the Kondo resonance, which manifests in the charge and spin current [12,13].…”

Section: Introductionmentioning

confidence: 98%

“…By treating the lead electrons as a mean field, to lowest order in , the magnetic lead γ splits the energy degeneracy on the dot by [13] …”

mentioning

confidence: 99%

Magnetic exchange and nonequilibrium spin current through interacting quantum dots

Hoffman

Tserkovnyak

2015

Phys. Rev. B

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We develop a theory for charge and spin currents between two canted magnetic leads flowing through a quantum dot with an arbitrary local interaction. For a noncollinear magnetic configuration, we calculate equilibrium and nonequilibrium currents biased by voltage or temperature difference or pumped by magnetic dynamics. We are able to explicitly separate the equilibrium and nonequilibrium contributions to the spin current, both of which can be written in terms of the full retarded Green's function on the dot. Taking the specific example of a single-level quantum dot with a large on-site Coulomb interaction, we calculate the total spin current near the Kondo regime, which we find to be generally enhanced in magnitude as compared to the noninteracting case.

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“…In the present work, we study the nonequilibrium Kondo effect and the transport properties in a QD coupled to graphene-based leads by solving the pseudogap Anderson model [36][37][38][39][40][41][42][43][44][45] with the equation of motion (EOM) technique [46][47][48]. In our studies, a magnetic field is applied to the QD causing a Kondo resonance splitting, and a finite on-site Coulomb interaction (U ) is considered resulting in a shift of the main QD energy level.…”

Section: Introductionmentioning

confidence: 99%

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

Grosu¹

2020

Beilstein J. Nanotechnol.

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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. 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. 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.

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Nonequilibrium spin-current detection with a single Kondo impurity

Cited by 16 publications

References 58 publications

Alternative equation of motion approach applied to transport through a quantum dot

Alternative equation of motion approach applied to transport through a quantum dot

Magnetic exchange and nonequilibrium spin current through interacting quantum dots

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

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