Electronic structure and optical properties of coupled quantum dots

Jh, Oh; Chang, Kee-Joo; Ihm, G.; Sj, Lee

doi:10.1103/physrevb.53.r13264

Cited by 50 publications

(23 citation statements)

References 16 publications

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“…[26]. Singlet-triplet crossings in the ground state of single [27] and coupled dots with two [28] to four [29,30] electrons in vertically coupled dots in the presence of a magnetic field perpendicular to the growth direction (B ⊥ in Fig. 1) have been predicted.…”

Section: Introductionmentioning

confidence: 84%

“…In contrast to previous theoretical work on coupled dots [23][24][25][26][27][28][29][30] the investigation presented here both takes into account quantum tunneling and includes in-plane magnetic fields (B in Fig. 1), leading to a much stronger suppression of the exchange energy than for B ⊥ (for very weakly confined dots, in-plane B fields can cause a singlet-triplet crossing, even in the absence of the Zeeman coupling).…”

Section: Introductionmentioning

confidence: 92%

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Spin interactions and switching in vertically tunnel-coupled quantum dots

2000

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We determine the spin exchange coupling J between two electrons located in two vertically tunnelcoupled quantum dots, and its variation when magnetic (B) and electric (E) fields (both in-plane and perpendicular) are applied. We predict a strong decrease of J as the in-plane B field is increased, mainly due to orbital compression. Combined with the Zeeman splitting, this leads to a singlettriplet crossing, which can be observed as a pronounced jump in the magnetization at in-plane fields of a few Tesla, and perpendicular fields of the order of 10 Tesla for typical self-assembled dots. We use harmonic potentials to model the confining of electrons, and calculate the exchange J using the Heitler-London and Hund-Mulliken technique, including the long-range Coulomb interaction. With our results we provide experimental criteria for the distinction of singlet and triplet states and therefore for microscopic spin measurements. In the case where dots of different sizes are coupled, we present a simple method to switch on and off the spin coupling with exponential sensitivity using an in-plane electric field. Switching the spin coupling is essential for quantum computation using electronic spins as qubits.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 92%

Spin interactions and switching in vertically tunnel-coupled quantum dots

2000

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“…In the theoretical aspect, 1993 Bryant [26] studied the energy spectra, charge densities, and correlation functions for interacting twoelectron systems in coupled dots as functions of the applied bias. In 1996 Oh et al [16] studied the electronic structure in coupled QDs with one or two electrons in magnetic fields. They were interested in the spin transitions of the ground state and the optical transitions between the energy levels.…”

Section: Introductionmentioning

confidence: 99%

Ground state transitions in vertically coupled N-layer single electron quantum dots

Xie

Wang

2003

Solid State Communications

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“…[4][5][6][7][8][9][10][11][12][13][14][15][16][17] A molecularlike feature of the electronic states can be expected in small double-quantum dots vertically coupled through a thin barrier. [15][16][17] In contrast to the laterally coupled doublequantum dots, circular symmetry still holds in the vertically coupled double-quantum dots.…”

Section: Introductionmentioning

confidence: 99%

Electron-correlation effects in transport through a double-quantum-dot molecule

Asano

1998

Phys. Rev. B

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The effects of the electron correlation on the electronic structure and transport in a pair of vertically coupled quantum dots are studied as functions of the number of electrons and the distance between the two dots by using a numerical diagonalization method. The electron correlation drastically affects the spin structure of the ground states when the number of electrons and the distance between the dots are sufficiently large. The electronic states with the large ͑small͒ spin momentum are stable when the number of electrons is an odd ͑even͒ integer. A physical picture of this characteristic behavior can be understood by an analogy to that of the electronic states in the Hubbard model near half filling. The Coulomb oscillation can be seen in the conductance of the electric current through the double-quantum dots. When the distance between the dots is large, the amplitudes of several conductance peaks are suppressed by the electron correlation.

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Electronic structure and optical properties of coupled quantum dots

Cited by 50 publications

References 16 publications

Spin interactions and switching in vertically tunnel-coupled quantum dots

Spin interactions and switching in vertically tunnel-coupled quantum dots

Ground state transitions in vertically coupled N-layer single electron quantum dots

Electron-correlation effects in transport through a double-quantum-dot molecule

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