Coherent spin–valley oscillations in silicon

Cai, Xinxin; Connors, Elliot J.; Edge, L. F.; Nichol, John

doi:10.1038/s41567-022-01870-y

Cited by 18 publications

(14 citation statements)

References 65 publications

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“…We empirically find that the data can be best fitted by two oscillations, hence the two cosine terms with their respective frequencies and phases are used. We speculate that this might result from initialising a mixed valley state, as there has been two slightly different spin resonances observed in the presence of a mixed valley-state before 34 , 36 . Our fits (Fig.…”

Section: Resultsmentioning

confidence: 96%

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Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe

Struck,

Volmer,

Visser

et al. 2024

Nat Commun

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Long-ranged coherent qubit coupling is a missing function block for scaling up spin qubit based quantum computing solutions. Spin-coherent conveyor-mode electron-shuttling could enable spin quantum-chips with scalable and sparse qubit-architecture. Its key feature is the operation by only few easily tuneable input terminals and compatibility with industrial gate-fabrication. Single electron shuttling in conveyor-mode in a 420 nm long quantum bus has been demonstrated previously. Here we investigate the spin coherence during conveyor-mode shuttling by separation and rejoining an Einstein-Podolsky-Rosen (EPR) spin-pair. Compared to previous work we boost the shuttle velocity by a factor of 10000. We observe a rising spin-qubit dephasing time with the longer shuttle distances due to motional narrowing and estimate the spin-shuttle infidelity due to dephasing to be 0.7% for a total shuttle distance of nominal 560 nm. Shuttling several loops up to an accumulated distance of 3.36 μm, spin-entanglement of the EPR pair is still detectable, giving good perspective for our approach of a shuttle-based scalable quantum computing architecture in silicon.

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Section: Resultsmentioning

confidence: 96%

“…1 c) 16 . The analogy to the two-spin EPR-pair is reasonable, since the simple picture holds that two of the three electrons fill one valley-orbit shell and the remaining electron is in a singlet state with the electron in the right QD 34 .…”

Section: Resultsmentioning

confidence: 99%

Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe

Struck,

Volmer,

Visser

et al. 2024

Nat Commun

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“…[205] Recently, Cai et al further utilized spin-valley mixing for S − T − and triplet-triplet oscillations in the Si/SiGe heterostructures. [210] 4.2. Engineering the HH-LH Mixing for Hole Qubits HH-LH mixing, a key feature of the valence band in semiconductor nanostructures, plays a critical role in hole qubits.…”

Section: Utilization Of Valley Splittingmentioning

confidence: 99%

“…further utilized spin–valley mixing for S − T − and triplet–triplet oscillations in the Si/SiGe heterostructures. [ 210 ]…”

Section: Engineering the Nanostructures And Operation Points For Bett...mentioning

confidence: 99%

Progress of Gate‐Defined Semiconductor Spin Qubit: Host Materials and Device Geometries

Liu,

Guan,

Luo

et al. 2024

Adv Funct Materials

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Quantum computing offers the potential to revolutionize information processing by exploiting the principles of quantum mechanics. Among the diverse quantum bit (qubit) technologies, silicon‐based semiconductor spin qubits have emerged as a promising contender due to their potential scalability and compatibility with existing semiconductor technologies. In this paper, the latest developments of spin qubits in gate‐defined semiconducting nanostructures made of silicon and germanium, starting from the basic properties of electron and hole states in group‐IV semiconductors, are reviewed. Specifically, various nanostructures that exploit their unique microscopic properties for qubit implementations, elaborating on the advances and challenges in experiments, are discussed. Strategies for enhancing qubit performance, such as designing new nanostructures and identifying suitable operating points, particularly those involving the valleys of electron qubits and the heavy‐hole–light‐hole mixing of hole qubits, are also highlighted. This comprehensive review thus provides valuable insights into the current state‐of‐the‐art in semiconductor quantum computing and suggests avenues for future research.

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“…Quantum technology has the potential to revolutionize modern industry by enabling more efficient computers, communication, and sensing devices. − Manipulating information precisely in quantum systems remains a challenge, crucial for achieving reliable and scalable quantum computing performance . Spin injection is one of the methods used to initialize, manipulate, and measure the spin states of electrons, which are fundamental to the creation of qubits in quantum computing. , Generally, spin currents are injected into ferromagnetic or diamagnetic materials to manipulate the spins of electrons and control the flow of information via the spin transfer torque effect, , spin waves, , spin Hall effect, and other spin–orbit coupling mechanisms. − Since the laser-induced ultrafast demagnetization of Ni film has been observed on the time scale of 1 ps, spin manipulation via laser pulse has gained significant attention due to its ability to speed up quantum computations and improve the efficiency of complex calculations. − One successful case is that, by utilizing a femtosecond laser excitation, a massive spin transfer can be obtained across a ferromagnet/semiconductor interface, i.e., spin injection into a diamagnetic MoS 2 monolayer from the cobalt layer .…”

Section: Introductionmentioning

confidence: 99%

Laser-Induced Ultrafast Spin Injection in All-Semiconductor Magnetic CrI₃/WSe₂ Heterobilayer

Guo,

Zhang,

Liu

et al. 2024

ACS Nano

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Spin injection stands out as a crucial method employed for initializing, manipulating, and measuring the spin states of electrons, which are fundamental to the creation of qubits in quantum computing. However, ensuring efficient spin injection while maintaining compatibility with standard semiconductor processing techniques is a significant challenge. Herein, we demonstrate the capability of inducing an ultrafast spin injection into a WSe 2 layer from a magnetic CrI 3 layer on a femtosecond time scale, achieved through real-time time-dependent density functional theory calculations upon a laser pulse. Following the peak of the magnetic moment in the CrI 3 sublayer, the magnetic moment of the WSe 2 layer reaches a maximum of 0.89 μ B (per unit cell containing 4 WSe 2 and 1 CrI 3 units). During the spin dynamics, spin-polarized excited electrons transfer from the WSe 2 layer to the CrI 3 layer via type-II band alignment. The large spin splitting in conduction bands and the difference in the number of spin-polarized local unoccupied states available in the CrI 3 layer lead to a net spin in the WSe 2 layer. Furthermore, we confirmed that the number of available states, the spin-flip process, and the laser pulse parameters play important roles during the spin injection process. This work highlights the dynamic and rapid nature of spin manipulation in layered all-semiconductor systems, offering significant implications for the development and enhancement of quantum information processing technologies.

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Coherent spin–valley oscillations in silicon

Cited by 18 publications

References 65 publications

Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe

Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe

Progress of Gate‐Defined Semiconductor Spin Qubit: Host Materials and Device Geometries

Laser-Induced Ultrafast Spin Injection in All-Semiconductor Magnetic CrI₃/WSe₂ Heterobilayer

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Coherent spin–valley oscillations in silicon

Cited by 18 publications

References 65 publications

Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe

Spin-EPR-pair separation by conveyor-mode single electron shuttling in Si/SiGe

Progress of Gate‐Defined Semiconductor Spin Qubit: Host Materials and Device Geometries

Laser-Induced Ultrafast Spin Injection in All-Semiconductor Magnetic CrI3/WSe2 Heterobilayer

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Laser-Induced Ultrafast Spin Injection in All-Semiconductor Magnetic CrI₃/WSe₂ Heterobilayer