Chapter 3. Towards spintronic quantum technologies with dopants in silicon

Morley, Gavin W.

doi:10.1039/9781782620280-00062

Cited by 9 publications

(9 citation statements)

References 70 publications

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“…Individual electronic and nuclear spins in silicon are among the prime contenders for realising scalable quantum technologies (Zwanenburg et al, 2013). In particular, due to its long-lived coherence and fast manipulation time, the electronic spin of a shallow donor in silicon is a promising candidate for implementing the quantum analogue of the classical bit -the qubit; in a solid state system (Morley, 2015).…”

Section: Motivationmentioning

confidence: 99%

Quantum control of hybrid nuclear–electronic qubits

et al. 2012

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Pulsed magnetic resonance allows the quantum state of electronic and nuclear spins to be controlled on the timescale of nanoseconds and microseconds respectively. The time required to flip dilute spins is orders of magnitude shorter than their coherence times, leading to several schemes for quantum information processing with spin qubits. Instead, we investigate 'hybrid nuclear-electronic' qubits consisting of near 50:50 superpositions of the electronic and nuclear spin states. Using bismuth-doped silicon, we demonstrate quantum control over these states in 32 ns, which is orders of magnitude faster than previous experiments using pure nuclear states. The coherence times of up to 4 ms are five orders of magnitude longer than the manipulation times, and are limited only by naturally occurring (29)Si nuclear spin impurities. We find a quantitative agreement between our experiments and an analytical theory for the resonance positions, as well as their relative intensities and Rabi oscillation frequencies. These results bring spins in a solid material a step closer to research on ion-trap qubits.

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Section: Motivationmentioning

confidence: 99%

Quantum control of hybrid nuclear–electronic qubits

et al. 2012

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“…Furthermore, DBs may be assembled into specific patterns for electronics or quantum simulations [6,14,17,18], including one-dimensional conducting or semiconducting wires [7,19,20]. They further serve as a starting configuration for atomically-precise dopant placement [21][22][23][24][25]. Hence tuning and manipulating the properties of DBs, e.g., charge states, may lead to a promising strategy to build a flexible atomic-scale platform of defects for electronic and quantum information technology applications.…”

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confidence: 99%

Optimizing surface defects for atomic-scale electronics: Si dangling bonds

Scherpelz

Galli

2017

Phys. Rev. Materials

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Surface defects created and probed with scanning tunneling microscopes are a promising platform for atomic-scale electronics and quantum information technology applications. Using first-principles calculations we demonstrate how to engineer dangling bond (DB) defects on hydrogenated Si(100) surfaces, which give rise to isolated impurity states that can be used in atomic-scale devices. In particular we show that sample thickness and biaxial strain can serve as control parameters to design the electronic properties of DB defects. While in thick Si samples the neutral DB state is resonant with bulk valence bands, ultrathin samples (1-2 nm) lead to an isolated impurity state in the gap; similar behavior is seen for DB pairs and DB wires. Strain further isolates the DB from the valence band, with the response to strain heavily dependent on sample thickness. These findings suggest new methods for tuning the properties of defects on surfaces for electronic and quantum information applications. Finally, we present a consistent and unifying interpretation of many results presented in the literature for DB defects on hydrogenated silicon surfaces, rationalizing apparent discrepancies between different experiments and simulations. arXiv:1702.07747v2 [cond-mat.mtrl-sci]

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“…In experiment, readout of the magnetisation of the Si:As is done via donor-bound exciton spectroscopy (D 0 X spectroscopy) [22,32]. This requires electrical detection, which can be achieved in a dilute 2D layer of P and As donors using STM hydrogen lithography to pattern highly conductive metallic-doped phosphorous pads into the same plane and overgrowing a protective thin-film of crystalline silicon with Molecular beam epitaxy.…”

Section: A Experimental Proposalmentioning

confidence: 99%

“…Initial successes in the realization of these applications in the last decades, mainly on AMO platforms such as trapped ions [8,9] and ultracold atoms in optical lattices [10][11][12][13], have also shown how hard it is to reach a regime where quantum computers are large enough to outperform their classical counterparts either due to limitations in the qubit addressability, interactions or sheer quantity. This scalability challenge could be more easily overcome in solid-state realizations, where a wide range of qubits have been proposed including Majorana fermions in nanowires [14,15], superconducting qubits [16][17][18], nitrogen-vacancy centers in diamond [19], quantum dots [20], and donor impurities in silicon [21,22].…”

Section: Introductionmentioning

confidence: 99%

Optically controlled entangling gates in randomly doped silicon

Crane

Schuckert

et al. 2019

Phys. Rev. B

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Randomly-doped silicon has many competitive advantages for quantum computation; not only is it fast to fabricate but it could naturally contain high numbers of qubits and logic gates as a function of doping densities. We determine the densities of entangling gates in randomly doped silicon comprising two different dopant species. First, we define conditions and plot maps of the relative locations of the dopants necessary for them to form exchange interaction mediated entangling gates. Second, using nearest neighbour Poisson point process theory, we calculate the doping densities necessary for maximal densities of single and dual-species gates. We find agreement of our results with a Monte Carlo simulation, for which we present the algorithms, which handles multiple donor structures and scales optimally with the number of dopants and use it to extract donor structures not captured by our Poisson point process theory. Third, using the moving average cluster expansion technique, we make predictions for a proof of principle experiment demonstrating the control of one species by the orbital excitation of another. These combined approaches to density optimization in random distributions may be useful for other condensed matter systems as well as applications outside physics.

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Chapter 3. Towards spintronic quantum technologies with dopants in silicon

Cited by 9 publications

References 70 publications

Quantum control of hybrid nuclear–electronic qubits

Quantum control of hybrid nuclear–electronic qubits

Optimizing surface defects for atomic-scale electronics: Si dangling bonds

Optically controlled entangling gates in randomly doped silicon

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