Resonant Tunneling Through Two Discrete Energy States

Vaart, N.C. van der; Godijn, S. F.; Nazarov, Yu. V.; Harmans, C.J.P.M.; Mooij, J. E.; Molenkamp, L. W.; Foxon, C.T.

doi:10.1103/physrevlett.74.4702

Cited by 242 publications

(222 citation statements)

References 15 publications

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“…For the two quantum dots in series, resonances are found when resonant levels in both dots are degenerate. The resulting Coulomb peaks are located on a hexagonal lattice and each peak has the width 2Γ where Γ is the intrinsic resonance width of a single dot [64,12]. In the presence of the detector one expects to observe a reduction of the peak height and a broadening of the peak width to 2(Γ +h/t d ).…”

Section: Experiments Of Sprinzak Et Almentioning

confidence: 99%

Phase coherent transmission through interacting mesoscopic systems

2001

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This is a review of the phase coherent transmission through interacting mesoscopic conductors. As a paradigm we study the transmission amplitude and the dephasing rate for electron transport through a quantum dot in the Coulomb blockade regime. We summarize experimental and theoretical work devoted to the phase of the transmission amplitude. It is shown that the evolution of the transmission phase may be dominated by non-universal features in the short-time dynamics of the quantum dot. The controlled dephasing in Coulomb coupled conductors is investigated. Examples comprise a single or multiple quantum dots in close vicinity to a quantum point contact. The current through the quantum point contact "measures" the state of the dots and causes dephasing. The dephasing rate is derived using widely different theoretical approaches. The Coulomb coupling between mesoscopic conductors may prove useful for future work on electron coherence and quantum computing.

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Section: Experiments Of Sprinzak Et Almentioning

confidence: 99%

Phase coherent transmission through interacting mesoscopic systems

2001

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“…SET between weakly coupled dots was interpreted as a sequential process which requires two discrete levels in the dots to be lined up in energy (taking due account for charging effects). This condition is fulfilled only at certain specific bias voltages which leads to sharp peaks in the I͑V ͒ curve [6,10]. Experiments on strongly coupled DDS provided evidence for coherent interdot coupling [11,12].…”

Section: Spectroscopy Of the Single-particle States Of A Quantum-dot mentioning

confidence: 97%

“…Recently, researchers focused on the interplay of two quantum dots in series coupled by a central tunneling barrier [5][6][7][8][9][10][11][12][13][14]. The bulk of existing work considers the intradot and interdot Coulomb interaction in double-dot systems (DDS) with many electrons [8][9][10][11][12][13][14].…”

Section: Spectroscopy Of the Single-particle States Of A Quantum-dot mentioning

confidence: 99%

“…The bulk of existing work considers the intradot and interdot Coulomb interaction in double-dot systems (DDS) with many electrons [8][9][10][11][12][13][14]. SET between weakly coupled dots was interpreted as a sequential process which requires two discrete levels in the dots to be lined up in energy (taking due account for charging effects).…”

mentioning

confidence: 99%

“…Rich spectra of discrete single-and many-electron states of such "artificial atoms" were studied by single-electron tunneling (SET) and capacitance spectroscopy [1]. SET through quantum dots, which are coupled via tunneling barriers to two contacts, leads to steps in the currentvoltage curve I͑V ͒, whenever discrete dot levels become energetically available for transport [2][3][4].Recently, researchers focused on the interplay of two quantum dots in series coupled by a central tunneling barrier [5][6][7][8][9][10][11][12][13][14]. The bulk of existing work considers the intradot and interdot Coulomb interaction in double-dot systems (DDS) with many electrons [8][9][10][11][12][13][14].…”

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confidence: 99%

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Spectroscopy of the Single-Particle States of a Quantum-Dot Molecule

et al. 1997

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We investigate low-temperature transport through two identical vertically coupled quantum dots in a triple-barrier heterostructure. The current-voltage curve exhibits two series of current steps of different magnitude. On the basis of magnetotunneling measurements, we relate the current steps to the single-particle levels of a quantum-dot molecule. From the absence of many-particle phenomena, an upper limit of 1 ns is determined for the energy-relaxation time in the double-dot system.[ S0031-9007(97) Quantum dots are zero-dimensional systems which exhibit confinement in all three dimensions of space. Rich spectra of discrete single-and many-electron states of such "artificial atoms" were studied by single-electron tunneling (SET) and capacitance spectroscopy [1]. SET through quantum dots, which are coupled via tunneling barriers to two contacts, leads to steps in the currentvoltage curve I͑V ͒, whenever discrete dot levels become energetically available for transport [2][3][4].Recently, researchers focused on the interplay of two quantum dots in series coupled by a central tunneling barrier [5][6][7][8][9][10][11][12][13][14]. The bulk of existing work considers the intradot and interdot Coulomb interaction in double-dot systems (DDS) with many electrons [8][9][10][11][12][13][14]. SET between weakly coupled dots was interpreted as a sequential process which requires two discrete levels in the dots to be lined up in energy (taking due account for charging effects). This condition is fulfilled only at certain specific bias voltages which leads to sharp peaks in the I͑V ͒ curve [6,10]. Experiments on strongly coupled DDS provided evidence for coherent interdot coupling [11,12].In this Letter, we investigate the single-particle regime of a strongly coupled DDS which was fabricated by imposing a submicron lateral confinement on a triplebarrier heterostructure. The I͑V ͒ curve exhibits steps reminiscent of SET in single dots. We attribute these current steps to SET through discrete single-particle states extended over both identical dots due to coherent interdot coupling. Thus, our DDS represents an ionized "artificial hydrogen molecule." From the magnitude of the steps, we estimate the energy-relaxation time in the DDS.The triple-barrier heterostructure was grown by molecular-beam epitaxy on an n 1 -type GaAs substrate. As shown in Fig. 1(a), the undoped active layers comprise two 6 nm GaAs quantum wells A and B which are strongly coupled to each other by a 1 nm thin center AlAs barrier and weakly coupled to two n-doped contact layers by 4 nm thick AlAs barriers. The Si doping profile of the contact layers is graded from 2 3 10 18 cm 23 to zero adjacent to the undoped triple-barrier region. Figure 1(b) shows the conduction-band profile V ͑z͒ of the heterostructure in growth direction for zero bias and V 200 mV. It was calculated with a Poisson solver in Thomas-Fermi approximation. From the wafer we fabricated free-standing pillars with Ohmic contacts [2] and measured their dc I͑V ͒ curves in a dilution refrigerator ...

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Quantum Gates by Coupled Quantum Dots and Measurement Procedure in Field-effect-transistor Structure

Tanamoto

2000

Fortschr. Phys.

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Coupled quantum‐dot system in semiconductor is considered to be one of the promising candidates of quantum computer. It will be most desirable that the quantum computing devices are implemented into the same substrate as the widely used LSI circuits. From this viewpoint, the quantum computer of coupled quantum dots of semiconductors is presented concentrating on the controlled‐NOT‐gate operation. The decoherence time of the quantum computation and the measurement procedure by field‐effect‐transistor structure are discussed.

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Resonant Tunneling Through Two Discrete Energy States

Cited by 242 publications

References 15 publications

Phase coherent transmission through interacting mesoscopic systems

Phase coherent transmission through interacting mesoscopic systems

Spectroscopy of the Single-Particle States of a Quantum-Dot Molecule

Quantum Gates by Coupled Quantum Dots and Measurement Procedure in Field-effect-transistor Structure

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