A model for many-body interaction effects in open quantum dot systems

Indlekofer, K. M.; Bird, Jonathan P.; Akis, R.; Ferry, D. K.; Goodnick, Stephen M.

doi:10.1088/0953-8984/15/2/314

Cited by 5 publications

(11 citation statements)

References 32 publications

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“…The suggestion of the experimental studies in section 4.2.1 is that the additional, logarithmic, term in the resistance arises from confinement-enhanced of the electron-electron interaction [38]. For this reason, we have formulated [40,102] a manybody description of transport in open dots that is based on the idea of the Anderson system, in which a single impurity level with an on-site electron-electron interaction is coupled to a one-dimensional lead [103][104][105][106][107]. In our case, the single impurity is interpreted as the quantum dot, which is coupled to two quantum-point-contact leads.…”

Section: Theoretical Modellingmentioning

confidence: 99%

“…To calculate transport properties from this model, we consider the diagonal non-equilibrium (due the non-constant chemical potential) many-body density-matrix. For numerical reasons, the continuum of k-states is discretized in our simulations, and we further employ a mean-field approach for the calculation of occupation numbers for statenumbers larger than 16 (The discretization in k-space must be chosen such that the resulting energy-spacing is small compared to k B T [102]). The current flowing through the system (and hence the conductance) can then be expressed in terms of the single-particle transmission probability (with its Fano-type resonance) and the occupation numbers [102].…”

Section: Theoretical Modellingmentioning

confidence: 99%

“…For numerical reasons, the continuum of k-states is discretized in our simulations, and we further employ a mean-field approach for the calculation of occupation numbers for statenumbers larger than 16 (The discretization in k-space must be chosen such that the resulting energy-spacing is small compared to k B T [102]). The current flowing through the system (and hence the conductance) can then be expressed in terms of the single-particle transmission probability (with its Fano-type resonance) and the occupation numbers [102]. In the inset to figure 35, we show the typical dependence of the conductance correction due to the interaction (assuming unity transmission) with varying chemical potential and temperature.…”

Section: Theoretical Modellingmentioning

confidence: 99%

See 2 more Smart Citations

Interference and interactions in open quantum dots

Bird¹,

Akis²,

Ferry³

et al. 2003

Rep. Prog. Phys.

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In this report, we review the results of our joint experimental and theoretical studies of electroninterference, and interaction, phenomena in open electron cavities known as quantum dots. The transport through these structures is shown to be heavily influenced by the remnants of their discrete density of states, elements of which remain resolved in spite of the strong coupling that exists between the cavity and its reservoirs. The experimental signatures of this density of states are discussed at length in this report, and are shown to be related to characteristic wavefunction scarring, involving a small number of classical orbits. A semiclassical analysis of this behaviour shows it to be related to the effect of dynamical tunnelling, in which electrons injected into the dot tunnel through classically forbidden regions of phase space, to access isolated regular orbits. The dynamical tunnelling gives rise to the formation of long-lived quasi-bound states in the open dots, and the many-body implications associated with electron charging at these resonances are also explored in this report.

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Section: Theoretical Modellingmentioning

confidence: 99%

Section: Theoretical Modellingmentioning

confidence: 99%

Section: Theoretical Modellingmentioning

confidence: 99%

See 1 more Smart Citation

Interference and interactions in open quantum dots

Bird¹,

Akis²,

Ferry³

et al. 2003

Rep. Prog. Phys.

Self Cite

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“…6 A description of the quantum transport in quantum dots is often based on model Hamiltonians containing phenomenological parameters such as coupling strengths or charging constants. [7][8][9] In many cases it is not always straightforward to relate quantitatively the above parameters to the physical processes they represent in the real system and sometimes it is not even obvious whether a model description is sufficient to capture the essential physics. At the same time, it is now well recognized that a detailed understanding and interpretation of the experiment might require a quantitative microscopical modeling of the system at hand, free from phenomenological parameters and not relying on model Hamiltonians which validity is poorly controlled.…”

Section: Introductionmentioning

confidence: 99%

Electron-electron interaction effects in transport through open dots: Pinning of resonant levels

2007

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The role of electron-electron interaction in transport properties of open quantum dots is studied. The selfconsistent full quantum-mechanical magnetotransport calculations within the Hartree, density-functional theory, and Thomas-Fermi approximations were performed, where a whole device, including the semiinfinitive leads, is treated on the same footing ͑i.e., the electron-electron interaction is accounted for both in the leads as well as in the dot region͒. The main finding of the present paper is the effect of pinning of the resonant levels to the Fermi energy due to the enhanced screening. Our results represent a significant departure from a conventional picture where a variation of external parameters ͑such as a gate voltage, magnetic field, etc.͒ causes the successive dot states to sweep past the Fermi level in a linear fashion. We instead demonstrate the highly nonlinear behavior of the resonant levels in the vicinity of the Fermi energy. The pinning of the resonant levels in open quantum dots leads to the broadening of the conduction oscillations in comparison to the one-electron picture. The effect of pinning becomes much more pronounced in the presence of the perpendicular magnetic field. This can be attributed to the enhanced screening efficiency because of the increased localization of the wave function. The strong pinning of the resonant energy levels in the presence of magnetic field can have a profound effect on transport properties of various devices operating in the edge state transport regime. We also critically examine an approximation often used in transport calculations where an inherently open system is replaced by a corresponding closed one.

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“…This question was posed in several theoretical studies with somewhat conflicting conclusions [15][16][17][18]. For example, Brouwer and Aleiner [15] argued that the Coulomb interactions enhance the weak localization and increase conductance fluctuations, whereas Brouwer, Lamacraft, and Flensberg [16] questioned these conclusions.…”

mentioning

confidence: 99%

Effect of Electron Interaction on Statistics of Conductance Oscillations in Open Quantum Dots: Does the Dephasing Time Saturate?

Ihnatsenka

Zozoulenko

2007

Phys. Rev. Lett.

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We perform self-consistent quantum transport calculations in open quantum dots taking into account the effect of electron interaction. We demonstrate that, in the regime of the ultralow temperatures 2 pi kappa BT < or = delta (delta being the mean-level spacing), the electron interaction strongly smears the conductance oscillations and thus significantly affects their statistics. Our calculations are in good quantitative agreement with the observed ultralow temperature statistics of Huibers et al. [Phys. Rev. Lett. 81, 1917 (1998)]. Our findings question a conventional interpretation of the ultralow temperature saturation of the coherence time in open dots which is based on the noninteracting theories, where the agreement with the experiment is achieved by introducing additional phenomenological channels of dephasing.

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A model for many-body interaction effects in open quantum dot systems

Abstract: We discuss the influence of the electron–electron interaction on transport properties of open quantum dot systems. Based on the idea of the Anderson model, we present interaction-induced temperature-dependent corrections to the conductance beyond the single-particle picture.

Cited by 5 publications

References 32 publications

Interference and interactions in open quantum dots

Interference and interactions in open quantum dots

Electron-electron interaction effects in transport through open dots: Pinning of resonant levels

Effect of Electron Interaction on Statistics of Conductance Oscillations in Open Quantum Dots: Does the Dephasing Time Saturate?

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