Electrically driven spin qubit based on valley mixing

Huang, W.; Veldhorst, Menno; Zimmerman, Neil M.; Dzurak, A. S.; Culcer, Dimitrie

doi:10.1103/physrevb.95.075403

Cited by 44 publications

(31 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…5) for similar driving amplitudes as used here the SOI-only EDSR can offer Rabi frequencies close to 1 MHz, which is around five times smaller than the micro-magnet based EDSR. Moreover, the Rabi frequency of the SOI-EDSR will strongly depend on the interface condition 36 (supplementary section S6) and can be difficult to control or improve. On the other hand, with improved design (stronger transverse gradient field) we can gain more advantage of the micro-magnets and drive even faster Rabi oscillations.…”

Section: Fig 4 Illustrates How the Inhomogeneous Magnetic Field Alonmentioning

confidence: 99%

See 1 more Smart Citation

Valley dependent anisotropic spin splitting in silicon quantum dots

et al. 2018

View full text Add to dashboard Cite

Spin qubits hosted in silicon (Si) quantum dots (QD) are attractive due to their exceptionally long coherence times and compatibility with the silicon transistor platform. To achieve electrical control of spins for qubit scalability, recent experiments have utilized gradient magnetic fields from integrated micro-magnets to produce an extrinsic coupling between spin and charge, thereby electrically driving electron spin resonance (ESR). However, spins in silicon QDs experience a complex interplay between spin, charge, and valley degrees of freedom, influenced by the atomic scale details of the confining interface. Here, we report experimental observation of a valley dependent anisotropic spin splitting in a Si QD with an integrated micro-magnet and an external magnetic field. We show by atomistic calculations that the spin-orbit interaction (SOI), which is often ignored in bulk silicon, plays a major role in the measured anisotropy. Moreover, inhomogeneities such as interface steps strongly affect the spin splittings and their valley dependence. This atomicscale understanding of the intrinsic and extrinsic factors controlling the valley dependent spin properties is a key requirement for successful manipulation of quantum information in Si QDs. arXiv:1702.06210v2 [cond-mat.mes-hall]

show abstract

Section: Fig 4 Illustrates How the Inhomogeneous Magnetic Field Alonmentioning

confidence: 99%

“…So, from this equation we can see that, without the Dresselhaus contribution, there is no angular dependence 35 or anisotropy in the spin splitting (or g-factor) for the different valley states. Now, for B ext along the 36 [110] and [110] crystal orientations, we get,…”

Section: Supplementary Materials For 'Valley Dependent Anisotropic Spmentioning

confidence: 99%

Valley dependent anisotropic spin splitting in silicon quantum dots

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Silicon provides an ideal environment for spin qubits thanks to its compatibility with industrial manufacturing technologies and the near-perfect nuclear-spin vacuum that isotopically enriched 28 Si provides 10,11 . Qubits can be encoded directly on the spins of individual nuclei, donor-bound electrons, or electrons confined in gatedefined quantum dots, or they can be encoded in subspaces provided by two or more spins 12 .…”

mentioning

confidence: 99%

Fidelity benchmarks for two-qubit gates in silicon

Huang

Yang

Chan

et al. 2019

Nature

398

383

View full text Add to dashboard Cite

Universal quantum computation will require qubit technology based on a scalable platform, together with quantum error correction protocols that place strict limits on the maximum infidelities for one-and two-qubit gate operations 1,2 . While a variety of qubit systems have shown high fidelities at the one-qubit level 3-9 , superconductor technologies have been the only solidstate qubits manufactured via standard lithographic techniques which have demonstrated twoqubit fidelities near the fault-tolerant threshold 5 . Silicon-based quantum dot qubits are also amenable to large-scale manufacture and can achieve high single-qubit gate fidelities (exceeding 99.9 %) using isotopically enriched silicon 10-12 . However, while two-qubit gates have been demonstrated in silicon 13-15 , it has not yet been possible to rigorously assess their fidelities using randomized benchmarking, since this requires sequences of significant numbers of qubit operations ( 20) to be completed with non-vanishing fidelity. Here, for qubits encoded on the electron spin states of gate-defined quantum dots, we demonstrate Bell state tomography with fidelities ranging from 80 % to 89 %, and two-qubit randomized benchmarking with an average Clifford gate fidelity of 94.7 % and average Controlled-ROT (CROT) fidelity of 98.0 %. These fidelities are found to be limited by the relatively slow gate times employed here compared with the decoherence times T * 2 of the qubits. Silicon qubit designs employing fast gate operations based on high Rabi frequencies 16-18 , together with advanced pulsing techniques 19 , should therefore enable significantly higher fidelities in the near future.Silicon provides an ideal environment for spin qubits thanks to its compatibility with industrial manufacturing technologies and the near-perfect nuclear-spin vacuum that isotopically enriched 28 Si provides 10,11 . Qubits can be encoded directly on the spins of individual nuclei, donor-bound electrons, or electrons confined in gatedefined quantum dots, or they can be encoded in subspaces provided by two or more spins 12 . Electrostatic gate electrodes allow initialization, readout 23 and, in some cases, manipulation of qubits 24 to be implemented with local electrical pulses. For qubits encoded on single spins, one-qubit gates can be driven using an AC magnetic field to perform electron spin resonance (ESR) directly 8,25 , through an AC electric field produced by a gate electrode combined with the magnetic field gradient from an on-chip micro-magnet 16,17,26 , or with an AC electric field acting on the spin-orbit field 27-29 . In enriched 28 Si devices such one-qubit gates have attained fidelities of 99.9 % or above 18,30,31 .Two-qubit gates, required to complete the universal gate set, are commonly implemented in spin systems as the √ SW AP 24,32 , the C-Phase 13,14 or the CROT 13,15 . While the √ SW AP and the C-Phase gates require fast temporal control of the exchange interaction J, accurately synchronized with spin resonance pulses, the CROT can also be implemented wit...

show abstract

“…4c, shows the same behavior, supporting our interpretation. The fact that I ds remains finite for B x may be explained by the fact that the (yz) symmetry plane is mildly broken by disorder and voltage biasing.In a recent work, Huang et al[45] proposed a mechanism for EDSR based on electrically induced oscillations of an electron across an atomic step at a Si/SiO 2 or a Si/SiGe heterointerface. The step enhances the SOC between the ground and the excited state of the same valley.…”

mentioning

confidence: 99%

Electrically driven electron spin resonance mediated by spin–valley–orbit coupling in a silicon quantum dot

Corna¹,

Bourdet²,

Maurand³

et al. 2018

npj Quantum Inf

101

View full text Add to dashboard Cite

The ability to manipulate electron spins with voltage-dependent electric fields is key to the operation of quantum spintronics devices, such as spin-based semiconductor qubits. A natural approach to electrical spin control exploits the spin-orbit coupling (SOC) inherently present in all materials. So far, this approach could not be applied to electrons in silicon, due to their extremely weak SOC. Here we report an experimental realization of electrically driven electron-spin resonance in a silicon-on-insulator (SOI) nanowire quantum dot device. The underlying driving mechanism results from an interplay between SOC and the multi-valley structure of the silicon conduction band, which is enhanced in the investigated nanowire geometry. We present a simple model capturing the essential physics and use tight-binding simulations for a more quantitative analysis. We discuss the relevance of our findings to the development of compact and scalable electron-spin qubits in silicon.

show abstract

Electrically driven spin qubit based on valley mixing

Cited by 44 publications

References 47 publications

Valley dependent anisotropic spin splitting in silicon quantum dots

Valley dependent anisotropic spin splitting in silicon quantum dots

Fidelity benchmarks for two-qubit gates in silicon

Electrically driven electron spin resonance mediated by spin–valley–orbit coupling in a silicon quantum dot

Contact Info

Product

Resources

About