Theoretical description of electronic properties of vertical gated quantum dots

We present a self-consistent Schroedinger-Poisson scheme for simulation of electrostatic quantum dots defined in gated two-dimensional electron gas formed at n-AlGaAs/GaAs heterojunction.The computational method is applied to a quantitative description of transport properties studied experimentally by Elzermann et al. [Appl. Phys. Lett. 84, 4617 (2004)]. The three-dimensional model describes the electrostatics of the entire device with a quantum dot that changes shape and floats inside a gated region when the applied voltages are varied. Our approach accounts for the metal electrodes of arbitrary geometry and configuration, includes magnetic field applied perpendicular to the growth direction, electron-electron correlation in the confined electron system and its interaction with the electron reservoir surrounding the quantum dot. We calculate the electric field, the space charge distribution as well as energies and wave functions of confined electrons to describe opening of two transport channels between the reservoir and the confined charge puddle. We determine the voltages for charging the dot with up to 4 electrons. The results are in a qualitative and quantitative agreement with the experimental data.

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“…[ 20,21,22,23,24,25,26,27 ]. Less attention was paid to dots based on the gated twodimensional electron gas.…”

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confidence: 99%

Quantum dot defined in a two-dimensional electron gas at an−AlGaAs∕GaAsheterojunction: Simulation of electrostatic potential and charging properties

2008

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“…The presence of repulsive scatterer simulates dopant with excess electrons. The choice of Gaussian impurity potential is not arbitrary as it has been exploited by several investigators [30][31][32][33][34][35].…”

Section: Methodsmentioning

confidence: 99%

Impurity Modulated Static Linear and First Nonlinear Polarizabilities of Doped Quantum Dots

Datta¹,

Ghosh

2012

ISRN Optics

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We explore the pattern of linear and first nonlinear optical (NLO) response of repulsive impurity doped quantum dots harmonically confined in two dimensions. The dopant impurity potential chosen assumes Gaussian form. The quantum dot is subject to a static electric field. For some fixed values of transverse magnetic field strength (ω c ), and harmonic confinement potential (ω 0 ), the influence of impurity strength (V 0 ), impurity stretch (ξ), and impurity location (r 0 ) on the diagonal components of static linear (α xx and α yy ), and the first NLO (β xxx and β yyy ) responses of the dot are computed through linear variational route. The investigation reveals the crucial roles played by the various impurity parameters in modulating these optical responses. Interestingly, maximization in the first NLO responses has been observed for some particular dopant location and at some particular value of spatial stretch of the dopant.

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“…The model confinement potential used most commonly 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19 is the two-dimensional (2D) cylindrically symmetric harmonic oscillator potential, which is a reasonable approximation of the confinement potential 28 in vertical quantum dots 23 .…”

Section: Introductionmentioning

confidence: 99%

Accuracy of the Hartree-Fock method for Wigner molecules at high magnetic fields

Szafran

Bednarek

Adamowski

et al. 2004

The European Physical Journal D - Atomic, Molecular and Optical

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Few-electron systems confined in two-dimensional parabolic quantum dots at high magnetic fields are studied by the Hartree-Fock (HF) and exact diagonalization methods. A generalized multicenter Gaussian basis is proposed in the HF method. A comparison of the HF and exact results allows us to discuss the relevance of the symmetry of the charge density distribution for the accuracy of the HF method. It is shown that the energy estimates obtained with the broken-symmetry HF wave functions become exact in the infinite magnetic-field limit. In this limit the charge density of the broken-symmetry solution can be identified with the classical charge distribution.

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Theoretical description of electronic properties of vertical gated quantum dots

Cited by 46 publications

References 37 publications

Quantum dot defined in a two-dimensional electron gas at an−AlGaAs∕GaAsheterojunction: Simulation of electrostatic potential and charging properties

Quantum dot defined in a two-dimensional electron gas at an−AlGaAs∕GaAsheterojunction: Simulation of electrostatic potential and charging properties

Impurity Modulated Static Linear and First Nonlinear Polarizabilities of Doped Quantum Dots

Accuracy of the Hartree-Fock method for Wigner molecules at high magnetic fields

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