Recent advances in hole-spin qubits

Fang, Yinan; Philippopoulos, Pericles; Culcer, Dimitrie; Coish, W. A.; Chesi, Stefano

doi:10.1088/2633-4356/acb87e

Cited by 21 publications

(5 citation statements)

References 199 publications

(440 reference statements)

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“…2 , and 1 2 , ±1 2 states represent heavy-hole (HH), light-hole (LH), and split-off bands, respectively [43,44]. The valence-band Hamiltonian can be expanded to form the 6 × 6 Lüttinger-Kohn Hamiltonian using these bases [37]:…”

Section: Hole Effective Mass In Ge 2dhgmentioning

confidence: 99%

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Recent progress in undoped group-IV heterostructures for quantum technologies

Tai,

2024

Mater. Quantum. Technol.

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Silicon has been a core material for digital computing owing to its high mobility, stability oxide interface, mature manufacturing technologies for more than half a century. While Moore’s law seems to further advance via various technologies to extend its expiration date, some intractable problems that requires processing times growing exponentially cannot be solved in a reasonable scale of time. Meanwhile, quantum computing is a promising tool to perform calculations much more efficiently than classical computing for certain types of problems. To realize a practical quantum computer, quantum dots on group-IV semiconductor heterostructures are promising due to the long decoherence time, scalability, and compatibility with the Si VLSI technology. In this review, we start with the advancement of group-IV undoped heterostructures since 2000 and review carrier transport properties in these undoped heterostructure. We also review the hole effective masses, spin-orbit coupling, and effective g-factors in the Ge-based heterostructures and conclude with a brief summary.

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Section: Hole Effective Mass In Ge 2dhgmentioning

confidence: 99%

“…For the extensive reviews on the Ge-based spin qubits, one can consult [43,44]. While the spin-based properties, such as SOC or g-factors, were reviewed in theoretical perspectives in those reports, there is not much focus on the experimental results of quantum transport in undoped group-IV heterostructures.…”

Section: Introductionmentioning

confidence: 99%

Recent progress in undoped group-IV heterostructures for quantum technologies

Tai,

2024

Mater. Quantum. Technol.

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“…Additionally, several other reviews share our focus on material platforms for spin qubits, covering materials for Si electron spin qubits, [ 41 ] , Ge [ 42 ] and GaAs [ 43 ] hole spin qubits. [ 44 ]…”

Section: Introductionmentioning

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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“…Group-IV materials (i.e., Ge, GeSn, SiGeSn, SiGe) exhibit a potential application in line with quantum science and technology, due to their unique spintronic and optoelectronic functionalities valuable for qubits. − By exploiting strain and bandgap engineering of these materials via intelligent buffer engineering − and precise control of tin (Sn) composition in GeSn or SiGeSn during materials synthesis, ,,− , it will offer widespread applications in Si-compatible photonics and quantum technology, provided that one could synthesize device-quality group-IV materials. In addition, downscaling of silicon (Si) transistors was possible by changing the device geometry from planar to fin field effect transistors (FinFETs).…”

Section: Introductionmentioning

confidence: 99%

Carrier Recombination Dynamics of Surface-Passivated Epitaxial (100)Ge, (110)Ge, and (111)Ge Layers by Atomic Layer Deposited Al₂O₃

Hudait

Johnston

Das

et al. 2023

ACS Appl. Electron. Mater.

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Germanium (Ge) and its heterostructures with compound semiconductors offer a unique optoelectronic functionality due to its pseudo-bandgap nature, that can be transformed to a direct bandgap material by providing strain and/or mixing with tin. Moreover, two crystal surfaces, (100)Ge and (110)Ge, that are technologically important for ultralow power fin or nanosheet transistors, could offer unprecedented properties with reduced surface defects after passivating these surfaces by atomic layer deposited (ALD) dielectrics. In this work, the crystallographically oriented epitaxial Ge/AlAs heterostructures were grown and passivated with ALD Al2O3 dielectrics, and the microwave photoconductive decay (μ-PCD) technique was employed to evaluate carrier lifetimes at room temperature. The X-ray photoelectron spectroscopy analysis reveals no role of orientation effect in the quality of the ALD Al2O3 dielectric on oriented Ge layers. The carrier lifetimes measured using the μ-PCD technique were benchmarked against unpassivated Ge/AlAs heterostructures. Excitation wavelengths of 1500 and 1800 nm with an estimated injection level of ∼1013 cm–3 were selected to measure the orientation-specific carrier lifetimes. The carrier lifetime was increased from 390 ns to 565 ns for (100)Ge and from 260 ns to 440 ns for (110)Ge orientations with passivation, whereas the carrier lifetime is almost unchanged for (111)Ge after passivation. This behavior indicates a strong dependence of the measured lifetime on surface orientation and surface passivation. The observed increase (>1.5×) in lifetime with Al2O3-passivated (100)Ge and (110)Ge surfaces is due to the lower surface recombination velocity compared to unpassivated Ge/AlAs heterostructures. The enhancement of carrier lifetime from passivated Ge/AlAs heterostructures with (100)Ge and (110)Ge surface orientations offers a path for the development of nanoscale transistors due to the reduced interface state density.

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Recent advances in hole-spin qubits

Cited by 21 publications

References 199 publications

Recent progress in undoped group-IV heterostructures for quantum technologies

Recent progress in undoped group-IV heterostructures for quantum technologies

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

Carrier Recombination Dynamics of Surface-Passivated Epitaxial (100)Ge, (110)Ge, and (111)Ge Layers by Atomic Layer Deposited Al₂O₃

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Recent advances in hole-spin qubits

Cited by 21 publications

References 199 publications

Recent progress in undoped group-IV heterostructures for quantum technologies

Recent progress in undoped group-IV heterostructures for quantum technologies

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

Carrier Recombination Dynamics of Surface-Passivated Epitaxial (100)Ge, (110)Ge, and (111)Ge Layers by Atomic Layer Deposited Al2O3

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Product

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Carrier Recombination Dynamics of Surface-Passivated Epitaxial (100)Ge, (110)Ge, and (111)Ge Layers by Atomic Layer Deposited Al₂O₃