Electric-field tuning of the valley splitting in silicon corner dots

Ibberson, David J.; Bourdet, L.; Abadillo-Uriel, J. C.; Ahmed, Imtiaz; Barraud, S.; Calderón, M. J.; Niquet, Yann-Michel; González-Zalba, M. Fernando

doi:10.1063/1.5040474

Cited by 34 publications

(23 citation statements)

References 39 publications

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“…Therefore, a reproducible and controllable valley splitting in silicon is on demand. Till now, several researches have been performed on valley splitting in silicon [162,[164][165][166][167][168]. As a whole, the valley splitting in quantum dots based on silicon MOS and SOI are in the range of 300-800 μeV and 610-880 μeV, respectively, and can be easily controlled by electric field [162,167].…”

Section: Materials Developmentsmentioning

confidence: 99%

“…Till now, several researches have been performed on valley splitting in silicon [162,[164][165][166][167][168]. As a whole, the valley splitting in quantum dots based on silicon MOS and SOI are in the range of 300-800 μeV and 610-880 μeV, respectively, and can be easily controlled by electric field [162,167]. A recent research even suggested that the single-electron valley splitting in silicon MOS quantum dots is both tunable and predictable, thus silicon MOS is a promising platform for qubit control [165].…”

Section: Materials Developmentsmentioning

confidence: 99%

See 1 more Smart Citation

Semiconductor quantum computation

Zhang

Cao

et al. 2018

National Science Review

127

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Semiconductors, a significant type of material in the information era, are becoming more and more powerful in the field of quantum information. In the last decades, semiconductor quantum computation was investigated thoroughly across the world and developed with a dramatically fast speed. The researches vary from initialization, control and readout of qubits, to the architecture of fault tolerant quantum computing. Here, we first introduce the basic ideas for quantum computing, and then discuss the developments of single-and twoqubit gate control in semiconductor. Till now, the qubit initialization, control and readout can be realized with relatively high fidelity and a programmable two-qubit quantum processor was even demonstrated. However, to further improve the qubit quality and scale it up, there are still some challenges to resolve such as the improvement of readout method, material development and scalable designs. We discuss these issues and introduce the forefronts of progress. Finally, considering the positive trend of the research on semiconductor quantum devices and recent theoretical work on the applications of quantum computation, we anticipate that semiconductor quantum computation may develop fast and will have a huge impact on our lives in the near future.

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Section: Materials Developmentsmentioning

confidence: 99%

Section: Materials Developmentsmentioning

confidence: 99%

Semiconductor quantum computation

Zhang

Cao

et al. 2018

National Science Review

127

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“…The smallest splittings, δ 20 ST and δ 11 ST Ã , may be associated with valley splittings, while the others involve combinations of valley and orbital excitations in QD mw . The relatively small δ 20 ST , which is associated with QD rf , is in the lower range of values reported for this class of devices (few tens to few hundreds of μeV [45][46][47][48][49]), which may be linked to a weak vertical electrical field and to the condition of the Si=SiO 2 interface. We note that the valley splitting may be enhanced by applying a negative back-gate voltage [47] or by reducing the number of electrons in the DQD, which strengthens vertical confinement.…”

Section: Magnetospectroscopymentioning

confidence: 65%

Spin Quintet in a Silicon Double Quantum Dot: Spin Blockade and Relaxation

Lundberg

Hutin

et al. 2020

Phys. Rev. X

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Spins in gate-defined silicon quantum dots are promising candidates for implementing large-scale quantum computing. To read the spin state of these qubits, the mechanism that has provided the highest fidelity is spin-to-charge conversion via singlet-triplet spin blockade, which can be detected in situ using gate-based dispersive sensing. In systems with a complex energy spectrum, like silicon quantum dots, accurately identifying when singlet-triplet blockade occurs is hence of major importance for scalable qubit readout. In this work, we present a description of spin-blockade physics in a tunnel-coupled silicon double quantum dot defined in the corners of a split-gate transistor. Using gate-based magnetospectroscopy, we report successive steps of spin blockade and spin-blockade lifting involving spin states with total spin angular momentum up to S ¼ 3. More particularly, we report the formation of a hybridized spin-quintet state and show triplet-quintet and quintet-septet spin blockade, enabling studies of the quintet relaxation dynamics from which we find T 1 ∼ 4 μs. Finally, we develop a quantum capacitance model that can be applied generally to reconstruct the energy spectrum of a double quantum dot, including the spin-dependent tunnel couplings and the energy splitting between different spin manifolds. Our results allow for the possibility of using Si complementary metal-oxide-semiconductor quantum dots as a tunable platform for studying high-spin systems.

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“…This allows bound electron states to accumulate, and creates a single QD. Corner dots [19,20] do not appear in the structure due to the narrow width of the channel. The FET top gate also acts as a plunger gate for the QD via capacitance C tg , allowing tuning of the next available energy level in the QD, which is labelled E QD , by adjusting V tg .…”

Section: Methodsmentioning

confidence: 99%

Nongalvanic Calibration and Operation of a Quantum Dot Thermometer

et al. 2021

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A cryogenic quantum dot thermometer is calibrated and operated using only a single non-galvanic gate connection. The thermometer is probed with radio-frequency reflectometry and calibrated by fitting a physical model to the phase of the reflected radio-frequency signal taken at temperatures across a small range. Thermometry of the source and drain reservoirs of the dot is then performed by fitting the calibrated physical model to new phase data. The thermometer can operate at the transition between thermally broadened and lifetime broadened regimes, and outside the temperatures used in calibration. Electron thermometry was performed at temperatures between 3.0 K and 1.0 K, in both a 1 K cryostat and a dilution refrigerator. In principle, the experimental setup enables fast electron temperature readout with a sensitivity of 4.0 ± 0.3 mK/ √ Hz, at kelvin temperatures. The non-galvanic calibration process gives a readout of physical parameters, such as the quantum dot lever arm. The demodulator used for reflectometry readout is readily available and very affordable.

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Electric-field tuning of the valley splitting in silicon corner dots

Cited by 34 publications

References 39 publications

Semiconductor quantum computation

Semiconductor quantum computation

Spin Quintet in a Silicon Double Quantum Dot: Spin Blockade and Relaxation

Nongalvanic Calibration and Operation of a Quantum Dot Thermometer

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