Kondo effect in a quantum dot—the atomic approach

Lobo, Thiago; Figueira, M. S.; Foglio, M. E.

doi:10.1088/0957-4484/17/24/019

Cited by 20 publications

(24 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A prototype system where Fano physics may be observed consists of a single quantum dot side-coupled to a quantum wire [3][4][5][6][7][8][9][10][11][12][13][14][15] . The Fano line shape results from an interference of the quantum amplitudes for the conduction pathway directly through the quantum wire without passing through the quantum dot and the indirect conduction pathway via the quantum dot.…”

Section: Introductionmentioning

confidence: 99%

Fano-Kondo effect in side-coupled double quantum dots at finite temperatures and the importance of two-stage Kondo screening

Žitko

2010

Phys. Rev. B

View full text Add to dashboard Cite

We study the zero-bias conductance through the system of two quantum dots, one of which is embedded directly between the source and drain electrodes, while the second dot is side-coupled to the first one through a tunneling junction. Modeling the system using the two-impurity Anderson model, we compute the temperaturedependence of the conductance in various parameter regimes using the numerical renormalization group. We consider the non-interacting case, where we study the extent of the departure from the conventional Fano resonance line shape at finite temperatures, and the case where the embedded and/or the side-coupled quantum dot is interacting, where we study the consequences of the coexistence of the Kondo and Fano effects. If the sidecoupled dot is very weakly interacting, the occupancy changes by two when the on-site energy crosses the Fermi level and a Fano-resonance-like shape is observed. If the interaction on the side-coupled dot is sizeable, the occupancy changes only by one and a very different line-shape results, which is strongly and characteristically temperature dependent. These results suggest an intriguing alternative interpretation of the recent experimental results study of the transport properties of the side-coupled double quantum dot [Sasaki et al., Phys. Rev. Lett. 103, 266806 (2009)]: the observed Fano-like conductance anti-resonance may, in fact, result from the two-stage Kondo effect in the regime where the experimental temperature is between the higher and the lower Kondo temperature.

show abstract

Section: Introductionmentioning

confidence: 99%

Fano-Kondo effect in side-coupled double quantum dots at finite temperatures and the importance of two-stage Kondo screening

Žitko

2010

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…We call this technique the atomic approach, not to be confused with the atomic solution of the Anderson limit. 38 The densities of states obtained with the method present a Kondo peak that has a correct height 9 1/π and exhibit the correct exponential variation of the Kondo temperature. 28 We calculate several density of states representative of the Kondo regime for finite correlation U, including the symmetrical case, in the single impurity Anderson model (SIAM).…”

Section: Discussionmentioning

confidence: 95%

General derivation of the Green's functions for the atomic approach of the Anderson model: application to a single electron transistor (SET)

2012

View full text Add to dashboard Cite

We consider the cumulant expansion of the periodic Anderson model (PAM) in the case of a finite electronic correlation U, employing the hybridization as perturbation, and obtain a formal expression of the exact one-electron Green's function (GF). This expression contains effective cumulants that are as difficult to calculate as the original GF, and the atomic approach consists in substituting the effective cumulants by the ones that correspond to the atomic case, namely by taking a conduction band of zeroth width and local hybridization. In a previous work (T. Lobo, M. S. Figueira, and M. E. Foglio, Nanotechnology 21, 274007 (2010)) we developed the atomic approach by considering only one variational parameter that is used to adjust the correct height of the Kondo peak by imposing the satisfaction of the Friedel sum rule. To obtain the correct width of the Kondo peak in the present work, we consider an additional variational parameter that guarantees this quantity. The two constraints now imposed on the formalism are the satisfaction of the Friedel sum rule and the correct Kondo temperature. In the first part of the work, we present a general derivation of the method for the single impurity Anderson model (SIAM), and we calculate several density of states representative of the Kondo regime for finite correlation U, including the symmetrical case. In the second part, we apply the method to study the electronic transport through a quantum dot (QD) embedded in a quantum wire (QW), which is realized experimentally by a single electron transistor (SET). We calculate the conductance of the SET and obtain a good agreement with available experimental and theoretical results. Copyright 2012 Author(s). This article is distributed under a Creative Commons Attribution 3.0 Unported License.

show abstract

“…In order to implement the atomic approach for the case of the infinite Coulomb energy [35], we begin with Eq. (2) expressed as…”

Section: B Atomic Approachmentioning

confidence: 99%

“…1. The setup is treated by using the single-impurity Anderson Hamiltonian [34] and the atomic approach [35,36] for the Green's functions, in which the STM tip and the "host+adatom" systems play, respectively, the roles of the cold and hot reservoirs. In the framework of the linear response theory, when voltage and temperature gradients are small, we derive analytical expressions for the thermoelectric coefficients characterizing the system.…”

Section: Introductionmentioning

confidence: 99%

Spin-dependent beating patterns in thermoelectric properties: Filtering the carriers of the heat flux in a Kondo adatom system

et al. 2014

View full text Add to dashboard Cite

We theoretically investigate the thermoelectric properties of a spin-polarized two-dimensional electron gas hosting a Kondo adatom hybridized with a STM tip. Such a setup is treated within the single-impurity Anderson model in combination with the atomic approach for the Green's functions. Due to the spin dependence of the Fermi wave numbers, the electrical and thermal conductances together with thermopower and Lorenz number reveal beating patterns as a function of the STM tip position in the Kondo regime. In particular, by tuning the lateral displacement of the tip with respect to the adatom vicinity, the temperature, and the position of the adatom level, one can change the sign of the Seebeck coefficient through charge and spin. This opens a possibility of the microscopic control of the heat flux analogously to that established for the electrical current.

show abstract

Kondo effect in a quantum dot—the atomic approach

Cited by 20 publications

References 45 publications

Fano-Kondo effect in side-coupled double quantum dots at finite temperatures and the importance of two-stage Kondo screening

Fano-Kondo effect in side-coupled double quantum dots at finite temperatures and the importance of two-stage Kondo screening

General derivation of the Green's functions for the atomic approach of the Anderson model: application to a single electron transistor (SET)

Spin-dependent beating patterns in thermoelectric properties: Filtering the carriers of the heat flux in a Kondo adatom system

Contact Info

Product

Resources

About