Dynamic nuclear polarization of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mtext>S</mml:mtext><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>29</mml:mn></mml:mrow></mml:mmultiscripts><mml:mtext>i</mml:mtext></mml:mrow></mml:math>nuclei in isotopically controlled phosphorus doped silicon

Hayashi, Hiroshi; Itahashi, T.; Itoh, Kohei M.; Vlasenko, L. S.; Vlasenko, M. P.

doi:10.1103/physrevb.80.045201

Cited by 29 publications

(30 citation statements)

References 46 publications

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“…The nuclear spin clusters contributing the most to central spin decoherence are those four-spin or three-spin clusters with small inter-nuclei distances (<1 nm), so that the energy cost of the pairwise flip-flop processes of two nuclear spins is significantly changed by the other nuclear spins in the cluster (see ‘Pseudospin model’ in Methods for details). The typical strength of the interaction between nuclear spins in such clusters is ~100 Hz, which is in the same order of the NMR linewidth of 29 Si in natural silicon samples23. In the calculations, we consider a bath volume with radius 8 nm from the central spin, corresponding to 5,000 nuclear spins.…”

Section: Resultsmentioning

confidence: 99%

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence

Wolfowicz

Zhao

et al. 2014

Nat Commun

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Central spin decoherence caused by nuclear spin baths is often a critical issue in various quantum computing schemes, and it has also been used for sensing single-nuclear spins. Recent theoretical studies suggest that central spin decoherence can act as a probe of many-body physics in spin baths; however, identification and detection of many-body correlations of nuclear spins in nanoscale systems are highly challenging. Here, taking a phosphorus donor electron spin in a 29Si nuclear spin bath as our model system, we discover both theoretically and experimentally that many-body correlations in nanoscale nuclear spin baths produce identifiable signatures in decoherence of the central spin under multiple-pulse dynamical decoupling control. We demonstrate that under control by an odd or even number of pulses, the central spin decoherence is principally caused by second- or fourth-order nuclear spin correlations, respectively. This study marks an important step toward studying many-body physics using spin qubits.

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Section: Resultsmentioning

confidence: 99%

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence

Wolfowicz

Zhao

et al. 2014

Nat Commun

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“…Single crystal semiconductors such as silicon are an excellent system to explore DNP, as they can exhibit a continuum of properties between those of metals and insulators depending on the doping concentration and temperature. [1][2][3][4][5][6][7] The electron spin resonance properties of shallow donors such as phosphorus and arsenic in silicon have been studied extensively. 8 At low temperatures and low doping concentrations the donor electrons are localized at the individual donor sites.…”

Section: Introductionmentioning

confidence: 99%

High-field Overhauser dynamic nuclear polarization in silicon below the metal–insulator transition

Dementyev

Cory

Ramanathan

2011

The Journal of Chemical Physics

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Single crystal silicon is an excellent system to explore dynamic nuclear polarization (DNP), as it exhibits a continuum of properties from metallic to insulating as a function of doping concentration and temperature. At low doping concentrations DNP has been observed to occur via the solid effect, while at very high-doping concentrations an Overhauser mechanism is responsible. Here we report the hyperpolarization of (29)Si in n-doped silicon crystals, with doping concentrations in the range of (1-3) × 10(17) cm(-3). In this regime exchange interactions between donors become extremely important. The sign of the enhancement in our experiments and its frequency dependence suggest that the (29)Si spins are directly polarized by donor electrons via an Overhauser mechanism within exchange-coupled donor clusters. The exchange interaction between donors only needs to be larger than the silicon hyperfine interaction (typically much smaller than the donor hyperfine coupling) to enable this Overhauser mechanism. Nuclear polarization enhancement is observed for a range of donor clusters in which the exchange energy is comparable to the donor hyperfine interaction. The DNP dynamics are characterized by a single exponential time constant that depends on the microwave power, indicating that the Overhauser mechanism is a rate-limiting step. Since only about 2% of the silicon nuclei are located within 1 Bohr radius of the donor electron, nuclear spin diffusion is important in transferring the polarization to all the spins. However, the spin-diffusion time is much shorter than the Overhauser time due to the relatively weak silicon hyperfine coupling strength. In a 2.35 T magnetic field at 1.1 K, we observed a DNP enhancement of 244 ± 84 resulting in a silicon polarization of 10.4 ± 3.4% following 2 h of microwave irradiation.

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“…One approach taken by the international collaboration led by Keio University was to enrich the phosphorus doped single silicon crystal with 29 Si to reduce the average distance between the phosphorus electrons and the 29 Si nuclear spins. [78][79][80][81] In this phenomenon, referred to as dynamical nuclear polarization, selective excitation of the symmetry prohibited ESR transitions in the phosphorus donor coupling to the nearby 29 Si, led to preferential relaxation to a certain 29 Si nuclear spin state (solid effect). This nuclear spin polarization around the phosphorus atom diffused through the crystal via nuclear spin diffusion ( 29 Si flip-flops).…”

Section: ] 28mentioning

confidence: 99%

“…However, this process is slow (>1 h) and the highest 29 Si polarization achieved was only~4%. [81] An efficient method would be to prepare electron spins that couple more directly to the 29 Si nuclear spins, similar to the way that an electron bound to a phosphorus atom couples strongly to the 31 P nuclear spin. To achieve this condition, the group led by Keio University employed vacancy-oxygen complexes in silicon that had 29 Si nearest neighbors.…”

Section: ] 28mentioning

confidence: 99%

Isotope engineering of silicon and diamond for quantum computing and sensing applications

2014

Self Cite

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Some of the stable isotopes of silicon and carbon have zero nuclear spin, whereas many of the other elements that constitute semiconductors consist entirely of stable isotopes that have nuclear spins. Silicon and diamond crystals composed of nuclear-spin-free stable isotopes ( 28 Si, 30 Si, or 12 C) are considered to be ideal host matrixes to place spin quantum bits (qubits) for quantum-computing and -sensing applications, because their coherent properties are not disrupted thanks to the absence of host nuclear spins. The present paper describes the state-of-theart and future perspective of silicon and diamond isotope engineering for development of quantum information-processing devices.

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Dynamic nuclear polarization ofS29inuclei in isotopically controlled phosphorus doped silicon

Cited by 29 publications

References 46 publications

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence

Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence

High-field Overhauser dynamic nuclear polarization in silicon below the metal–insulator transition

Isotope engineering of silicon and diamond for quantum computing and sensing applications

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