Stark Tuning of Donor Electron Spins in Silicon

Bradbury, F. R.; Tyryshkin, Alexei M.; Sabouret, Guillaume; Bokor, J.; Schenkel, T.; Lyon, Stephen

doi:10.1063/1.2730277

Cited by 16 publications

(23 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The electric field creates a Stark shift of the electron g * -factor due to the small but finite spin-orbit coupling. Tight binding simulations [18] and measurements on donors in silicon [28] indicate a quadratic Stark shift in g * . By fitting our data we find a quadratic Stark coefficient of η 2 = 2.2 nm 2 /V 2 , comparable to that calculated in Rahman et al [18].…”

mentioning

confidence: 90%

“…The relevant coherence times (T * 2 , T H 2 and T CP M G 2 ) of our system exceed by two orders of magnitude the times of previous quantum dot qubits [14,15], while the fastest measured Rabi period of 400 ns combined with our T CP M G 2 = 28 ms enables more than 10 5 computational operations within the qubit coherence time. A recent experiment [29] on a phosphorus donor qubit in 28 Si found out that T CP M G 2 is limited by Johnson-Nyquist thermal noise delivered via the onchip ESR line, which is also the likely scenario for the quantum dot qubit given the comparable coherence times. This opens the possibility to increase coherence times even further.…”

mentioning

confidence: 99%

See 1 more Smart Citation

An addressable quantum dot qubit with fault-tolerant control-fidelity

et al. 2014

View full text Add to dashboard Cite

Exciting progress towards spin-based quantum computing [1,2] has recently been made with qubits realized using nitrogen-vacancy (N-V) centers in diamond and phosphorus atoms in silicon [3], including the demonstration of long coherence times made possible by the presence of spin-free isotopes of carbon [4] and silicon [5]. However, despite promising single-atom nanotechnologies [6], there remain substantial challenges in coupling such qubits and addressing them individually. Conversely, lithographically defined quantum dots have an exchange coupling that can be precisely engineered1, but strong coupling to noise has severely limited their dephasing times and control fidelities. Here we combine the best aspects of both spin qubit schemes and demonstrate a gate-addressable quantum dot qubit in isotopically engineered silicon with a control fidelity of 99.6%, obtained via Clifford based randomized benchmarking and consistent with that required for fault-tolerant quantum computing [7,8]. This qubit has orders of magnitude improved coherence times compared with other quantum dot qubits, with T * 2 = 120 µs and T2 = 28 ms. By gate-voltage tuning of the electron g * -factor, we can Stark shift the electron spin resonance (ESR) frequency by more than 3000 times the 2.4 kHz ESR linewidth, providing a direct path to large-scale arrays of addressable high-fidelity qubits that are compatible with existing manufacturing technologies.The seminal work by Loss and DiVincenzo[1] to encode quantum information using the spin states of semiconductor quantum dots generated great excitement, as it fulfilled what were then understood to be the key criteria[2] for quantum computation, and has already led to the realization of 2-qubit operations such as the √ SWAP[9, 10] and CPHASE [11]. However, the limited lifetime and the associated fidelity of the quantum state represent a significant hurdle for the semiconductor quantum dot qubits realized thus far. A dephasing time up to T * 2 = 37 ns [12], improved to T * 2 = 94 ns[13] using nuclear spin bath control, has been recorded for quantum dot spin qubits in GaAs/AlGaAs. A longer T * 2 = 360 ns has been achieved using Si/SiGe quantum dots [14]. The main strategy to improve these times has involved applying pulse sequences developed for bulk magnetic resonance, and we can specify a T 2 according to the applied pulse sequence. Using a Hahn echo sequence the coherence time of GaAs-based qubits has been extended to T 28 Si), we remove the dephasing effect of the nuclear spin bath present in these previous studies, and show that all of the above coherence times can be improved by orders of magnitude. These long coherence times, in particular the dephasing time T * 2 , lead to low control error rates and the high fidelities that will be required for large-scale, fault tolerant quantum computing [7,8].In contrast with quantum dots, electron spin qubits localized on atoms or defects have been realized in almost spinfree environments, showing coherence times approaching [4] and even exceeding seco...

show abstract

mentioning

confidence: 90%

mentioning

confidence: 99%

An addressable quantum dot qubit with fault-tolerant control-fidelity

et al. 2014

View full text Add to dashboard Cite

show abstract

“…The use of donor electron spins has further advantages of consistency (since each atom is identical) and tuneability (e.g. through the Stark shift 16 ), while the donor atom's nuclear spin can be employed as a quantum memory for longer term storage 17 .…”

mentioning

confidence: 99%

A single-atom electron spin qubit in silicon

Pla

Tan

Dehollain

et al. 2012

Nature

758

814

View full text Add to dashboard Cite

A single atom is the prototypical quantum system, and a natural candidate for a quantum bit, or qubit--the elementary unit of a quantum computer. Atoms have been successfully used to store and process quantum information in electromagnetic traps, as well as in diamond through the use of the nitrogen-vacancy-centre point defect. Solid-state electrical devices possess great potential to scale up such demonstrations from few-qubit control to larger-scale quantum processors. Coherent control of spin qubits has been achieved in lithographically defined double quantum dots in both GaAs (refs 3-5) and Si (ref. 6). However, it is a formidable challenge to combine the electrical measurement capabilities of engineered nanostructures with the benefits inherent in atomic spin qubits. Here we demonstrate the coherent manipulation of an individual electron spin qubit bound to a phosphorus donor atom in natural silicon, measured electrically via single-shot read-out. We use electron spin resonance to drive Rabi oscillations, and a Hahn echo pulse sequence reveals a spin coherence time exceeding 200 µs. This time should be even longer in isotopically enriched (28)Si samples. Combined with a device architecture that is compatible with modern integrated circuit technology, the electron spin of a single phosphorus atom in silicon should be an excellent platform on which to build a scalable quantum computer.

show abstract

“…Here, we have included the E-field dependence of the g factor, which was ignored in previous donor spin qubit proposals 17 , but was measured in ESR experiments 18 . The selectivity of single qubit rotation in the canonical scheme relies on Stark shift of A(E) only to bring v in resonance with the microwave field (v MW ), while all others qubits stay sufficiently detuned.…”

mentioning

confidence: 99%

Spin readout and addressability of phosphorus-donor clusters in silicon

et al. 2013

View full text Add to dashboard Cite

The spin states of an electron bound to a single phosphorus donor in silicon show remarkably long coherence and relaxation times, which makes them promising building blocks for the realization of a solid-state quantum computer. Here we demonstrate, by high-fidelity (93%) electrical spin readout, that a long relaxation time T 1 of about 2 s, at B ¼ 1.2 T and TE100 mK, is also characteristic of electronic spin states associated with a cluster of few phosphorus donors, suggesting their suitability as hosts for spin qubits. Owing to the difference in the hyperfine coupling, electronic spin transitions of such clusters can be sufficiently distinct from those of a single phosphorus donor. Our atomistic tight-binding calculations reveal that when neighbouring qubits are hosted by a single phosphorus atom and a cluster of two phosphorus donors, the difference in their electron spin resonance frequencies allows qubit rotations with error rates E10 À 4 . These results provide a new approach to achieving individual qubit addressability.

show abstract

Stark Tuning of Donor Electron Spins in Silicon

Cited by 16 publications

References 14 publications

An addressable quantum dot qubit with fault-tolerant control-fidelity

An addressable quantum dot qubit with fault-tolerant control-fidelity

A single-atom electron spin qubit in silicon

Spin readout and addressability of phosphorus-donor clusters in silicon

Contact Info

Product

Resources

About