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

Ihnatsenka, S.; Zozoulenko, Igor

doi:10.1103/physrevlett.99.166801

Cited by 11 publications

(20 citation statements)

References 29 publications

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“…We also demonstrate that in the regime of the ultralow temperatures 2π k B T ( being the mean-level spacing), the electron interactions 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 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 [18].…”

Section: Resultssupporting

confidence: 88%

“…We consider an open structure (e.g. a quantum point contact (QPC) or a quantum dot) placed between two semi-infinite electron reservoirs [16][17][18]. A schematic layout of the device is illustrated in figure 6.…”

Section: Model and Methodsmentioning

confidence: 99%

“…The difference between these approaches is the shape of the total confining potential: in one-electron transport simulations one typically starts with a model hard wall confinement, whereas the TF approximation gives a rather smooth potential which represents a good approximation to the actual confinement. Figure 10(a) shows the conductance of the open quantum dot calculated in the Hartree and TF approximations (interacting and noninteracting electrons respectively) for T = 50 mK [18]. All the results discussed in this paper correspond to one propagating mode in the quantum point contact (QPC) openings.…”

Section: Open Dotsmentioning

confidence: 99%

See 2 more Smart Citations

Electron interaction and spin effects in quantum wires, quantum dots and quantum point contacts: a first-principles mean-field approach

Zozoulenko¹,

Ihnatsenka²

2008

J. Phys.: Condens. Matter

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We have developed a mean-field first-principles approach for studying electronic and transport properties of low dimensional lateral structures in the integer quantum Hall regime. The electron interactions and spin effects are included within the spin density functional theory in the local density approximation where the conductance, the density, the effective potentials and the band structure are calculated on the basis of the Green's function technique. In this paper we present a systematic review of the major results obtained on the energetics, spin polarization, effective g factor, magnetosubband and edge state structure of split-gate and cleaved-edge overgrown quantum wires as well as on the conductance of quantum point contacts (QPCs) and open quantum dots. In particular, we discuss how the spin-resolved subband structure, the current densities, the confining potentials, as well as the spin polarization of the electron and current densities in quantum wires and antidots evolve when an applied magnetic field varies. We also discuss the role of the electron interaction and spin effects in the conductance of open systems focusing our attention on the 0.7 conductance anomaly in the QPCs. Special emphasis is given to the effect of the electron interaction on the conductance oscillations and their statistics in open quantum dots as well as to interpretation of the related experiments on the ultralow temperature saturation of the coherence time in open dots.

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Section: Resultssupporting

confidence: 88%

Section: Model and Methodsmentioning

confidence: 99%

Section: Open Dotsmentioning

confidence: 99%

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Electron interaction and spin effects in quantum wires, quantum dots and quantum point contacts: a first-principles mean-field approach

Zozoulenko¹,

Ihnatsenka²

2008

J. Phys.: Condens. Matter

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“…(It is noteworthy that in conventional 2DEG systems these two methods lead to very similar results for self-consisted potentials and electron densities; see, e.g., Ref. 38.) It should be however noted that the full self-consistent quantum mechanical treatment of the systems considered in the present study is beyond the current computational capabilities.…”

Section: Fig 3 (Color Online)mentioning

confidence: 65%

Interaction-induced enhancement ofgfactor in graphene

2012

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We study the effect of electron interaction on the spin splitting and the g factor in graphene in a perpendicular magnetic field using the Hartree and the Hubbard approximations within the Thomas-Fermi model. We found that the effective g factor is enhanced in comparison to its free-electron value g = 2 and oscillates as a function of the filling factor ν in the range 2 g * 4 reaching maxima at ν = 4N = 0, ± 4, ± 8, . . . and minima at ν = 4 N + 1 2 = ±2, ± 6, ± 10, . . ., with N being the Landau level index. We outline the role of charged impurities in the substrate, which are shown to suppress the oscillations of the g * factor. This effect becomes especially pronounced with the increase of the impurity concentration, when the effective g factor becomes independent of the filling factor, reaching a value of g * ≈ 2.3. A relation to the recent experiment is discussed.

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“…To outline the role of the electron-electron interaction in the presence of magnetic field B, we use the Thomas-Fermi approach and perform two different calculations for the self-consistent total potential. Here it is important to mention that the Thomas-Fermi approximation corresponds well with the quantum-mechanical methods for the calculation of electron density and electrostatic potential in semiconductor as well as graphene systems [34,35].…”

Section: Introductionmentioning

confidence: 97%

Electron-electron interactions in graphene field-induced quantum dots in a high magnetic field

2015

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We study the effect of electron-electron interaction in graphene quantum dots defined by an external electrostatic potential and a high magnetic field. To account for the electron-electron interaction, we use the Thomas-Fermi approximation and find that electron screening causes the formation of compressible strips in the potential profile and the electron density. We numerically solve the Dirac equations describing the electron dynamics in quantum dots, and we demonstrate that compressible strips lead to the appearance of plateaus in the electron energies as a function of the magnetic field. Finally, we discuss how our predictions can be observed using the Kelvin probe force microscope measurements.

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

Cited by 11 publications

References 29 publications

Electron interaction and spin effects in quantum wires, quantum dots and quantum point contacts: a first-principles mean-field approach

Electron interaction and spin effects in quantum wires, quantum dots and quantum point contacts: a first-principles mean-field approach

Interaction-induced enhancement ofgfactor in graphene

Electron-electron interactions in graphene field-induced quantum dots in a high magnetic field

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